1

Jim Molinaro

Howard Ryan

SHOOTING INCIDENT ANALYSIS and RECONSTRUCTION

FORENSIC TRAINING SOURCE

COURSE OBJECTIVES• Terminology• Internal, external and terminal ballistics• Gunshot residue and range of fire• Identifying, detecting, measuring and describing bullet

marks• Behavior of bullets on varying target surfaces• Bullet perforation, penetration, deflection and ricochet

factors• Proper recording and documentation of bullet marks• Motor vehicles as target surfaces• Flight path documentation, description and

reconstruction• Using drawing software such as CAD, Poser, etc. to

illustrate data and findings• Report Writing – putting analysis and conclusions into

words• Explaining and describing analysis and reconstruction• ****Practicals*** ****Practicals*** ****Practicals***

BASIC COURSE !!!

• Shooting and Crime Scene Reconstruction is an advanced technique

• Requires continued specialized training not just in shooting analysis but in other disciplines, i.e. bloodstain

• Requires experience, lots of it

• Your ability to give opinions/conclusions can only be based on the level of training you have received and experience you have acquired in this field

Section IBallistics

Ballistics• The term ballistics refers to the science of the travel of a

projectile in flight.

• Internal – travel down the barrel upon firing

• External – path through the air

• Terminal – contact with target and path into/through a target

• The wounding or damaging producing potential of projectiles is a complex matter.

• Laceration and crushing - Low velocity bullets, as in handguns, that travel less than 1000 fps do virtually all their damage via crushing.

• Cavitation - Cavitation is significant with projectiles traveling in excess of 1000 fps. A "permanent" cavity is caused by the path of the bullet itself, whereas a "temporary" cavity is formed by continued forward acceleration of the medium (air or tissue) in the wake of the bullet, causing the wound cavity to be stretched outward.

• Shock waves - Shock waves compress the medium and travel ahead of the bullet, as well as to the sides, but these waves last only a few microseconds and do not cause profound destruction at low velocity. At high velocity, generated shock waves can reach up to 200 atmospheres of pressure.

Manufacturer Considerations in Bullet Design

• Generally three areas:

• Bullet Accuracy

• the ability of a bullet to repeatedly hit a target at the same line of sight at all ranges

• Bullet Efficiency

• The ability of a bullet to deliver a higher percentage of its speed and energy downrange

• The less speed and energy lost in traveling from Point A (Muzzle) to Point B (Target) the more speed and energy it can deliver to the target

• Bullet Terminal Performance

• The ability of a bullet by its design to release the greatest amount of its remaining speed and energy upon impact into a target

2

Internal Ballistics

• The controlled expansion of burning gunpowder generates pressure (force/area).

• The area the force is applied to the base of the bullet (equivalent to diameter of barrel) and is a constant.

• Therefore, the energy transmitted to the bullet (with a given mass) will depend upon mass times force times the time interval over which the force is applied.

• The last of these factors is a function of barrel length. Bullet travel through a gun barrel is characterized by increasing acceleration as the expanding gases push on it.

• Up to a point, the longer the barrel, the greater the acceleration

Internal Ballistics

• Bullets fired from a rifle will have more energy than similar bullets fired from a handgun.

• More powder can also be used in rifle cartridges because the bullet chambers can be designed to withstand greater pressures (70,000 psi vs. 40,000 psi for handgun chamber).

External Ballistics

• As the bullet exits the barrel it possess energy in the form of kinetic energy.

• The formula describing this kinetic energy is:• Kinetic Energy (KE) = 1/2 mV2

•m = mass

•V = velocity• Increases in bullet velocity have a greater effect on KE than

increases in bullet mass or barrel length

• KE is the bullet's energy as it leaves the muzzle but the amount of total KE delivered to the target varies as air resistance is encountered and external factors influence bullet flight

Drag is also influenced by bullet spin. The faster the spin, the less likely a bullet will "yaw" or turn sideways and tumble. Bullets do not typically follow a straight line to the target. Rotational forces are in effect that keep the bullet off a straight axis of flight.

Terminal Ballistics• The cause and effects produced as a result of a

bullet impacting a target surface• Dependent upon:

• Bullet design• Mass of the bullet• Velocity of the bullet• KE remaining upon impact• Resistance of the target• Deformation of the bullet• Amount of KE lost to the target surface

• Tumbling has a lot to do with the injury/damage pattern of a bullet on the target, termed "terminal ballistics."

• A short, high velocity bullet begins tumbling more rapidly in tissue.

• This causes more tissue to be displaced and imparts more of the KE to the target.

3

• A longer, heavier bullet might have more KE at a longer range when it hits the target, but it may penetrate so well that it exits the target with much of its KE remaining.

• Even a bullet with a low KE can impart significant tissue damage if it can be designed to give up all of the KE into the target and the target is at short range.

• Deformation of the bullet is a function of bullet design, mass, velocity and the resistance encountered

• In humans the degree of damage (wounding potential) is a function of the extent to which a given bullet having a given mass, traveling at a given velocity possessing a given KE impacts a target surface and the resultant Permanent Wound Cavity and Temporary Wound Cavity produced

Wound Cavity Profile as a Function of Velocity

Wound Cavity Profile as a Function of Deformation

Permanent and Temporary Cavity Production

Wound Cavity Production from a Handgun Bullet

Temporary Cavity

Permanent Cavity

4

Wound Cavity Production Comparison in Gel ‐Handguns

Section IIAnalysis of Firearms 

Related Evidence

Laboratory Examination of Firearms and Related Evidence

• Biological:• Should be examined for biological evidence – FIRST!!

• Blood, tissue, bone, hair

• Trace:• Should be examined for trace evidence as well as

patterned markings

• Bullets may pick up fibers, paint, concrete, wood, sheetrock, glass, soil, asphalt or potentially any other material

• The presence of bio and/or trace may tell us a great deal about the flight path of a bullet through a crime scene and which target, intermediate target and/or final target surfaces that may have been impacted• Can support or refute other aspects of a shooting

analysis and potential flight paths determined through other methods

• Friction Ridge Processing

• Firearms Analysis (unique tool marks) – LAST!!

Biological Evidence

Blood

Trace Evidence

PaintFibers

DrywallCompositeBoard

Friction Ridge

5

Firearms Analysis

• When a barrel is made two types of marks are left on the bore of the barrel• Class characteristics• Unique microscopic characteristics (striations)

• These characteristics are imparted onto the bullet as it travels through the bore of the barrel

• Class characteristics include:• # of lands and grooves• Width of lands and grooves• Direction of twist• Diameter of bore• Rate of twist

• Class characteristics can be used to determine• Caliber• Possible manufacturer (unique to certain manufacturers)

Microscopic Examinations by a Firearms Related Evidence Tool Mark Examiner

• TYPES OF COMPARISONS• Questioned Cartridge

to Questioned Cartridge

• Firing Pin

• Extractor Mark

• Questioned Cartridge to Exemplar Cartridge

• Firing Pin

• Extractor Mark

• Questioned Bullet to Questioned Bullet

• Question Bullet to Exemplar Bullet

• CANNOT DO: BULLET to SHELL

Lands and Grooves Firearms AnalysisLands and Grooves

Bullet to Bullet Comparison

Control UnknownControl Unknown

Firearms AnalysisCartridge to Cartridge Comparison

Control Unknown

Firearms AnalysisFiring Pin Comparison

6

Firearms AnalysisExtractor Marks 3D Imaging

Firearms Analysis3 D Imaging

Range of Fire Estimation

• Firearms examiners are asked to estimate range

• Evidence may be found by evaluating type and shape of gunshot residue, closeness of discharge of weapon to victim, size and shape of wound (s) and effects of discharge

• Determined from gunshot residues and/or pellet patterns

• Requires:

• Original powder pattern from gunshot residue

• Firearm used to fire the pattern

• Ammunition from same lot used to fire pattern

• Knowledge of the weather conditions

Gunshot Residue

• Firing a weapon produces combustion of the primer and powder of the cartridge.

• The residue of the combustion products, or unburned primer or powder components, can be used to detect a fired cartridge.

• Residue may be found on the skin or clothing of the person who fired the gun, on an entrance wound of a victim, or on other target materials at the scene.

• The discharge of a firearm, particularly a revolver, can deposit residues even to persons at close proximity, so interpretations as to who fired the weapon should be made with caution.

• Two types of gunshot residue

• Primer Residues

• Gunpowder Residues

7

Primer Residues

• May contain elements - lead (Pb), barium (Ba), or antimony (Sb). Usually, all three are present. Less common elements include aluminum (Al), sulfur (S), tin (Sn), calcium (Ca), potassium (K), chlorine (Cl), or silicon (Si).

• Some cartridges do not contain these elements

• .22 rimfires may not contain all of these elements

• Deposited by:• Firing a gun

• Handling a recently fired gun

• Being in close proximity when a gun is discharged

• Therefore, a “positive result” is not proof positive that a person fired a gun

• Residues can be removed by washing the hands

• Normally residues won’t be present after 3-5 hours on a living person not taking any active measures to remove any residue

Gunpowder Residues

• Include:

• Carbon soot

• Unburned gunpowder

• Partially burned gunpowder

• The presence of these gunpowder residues on the target (i.e. clothing and/or skin, objects) canindicate a muzzle to target distance

• Absence of gunpowder residues can indicate target beyond the range of deposition

CONTACT 1” 6”

12” 18”

8

Detection of Gunshot Residues from Individuals

• The major methods for detection of primer residues are neutron activation analysis (NAA), atomic absorption Spectrophotometry (AAS), and scanning electron microscopy with energy dispersive analysis (SEM-EDA).

• For these methods, samples must be obtained from the skin surfaces of a victim at the scene. Delay in obtaining residues, movement, or washing of the body (prior to autopsy) will diminish or destroy gunshot residues

Detection of Gunshot Residues on Target Surfaces

• Microscopic Examination

• Infrared Examination

• Gunpowder residues exhibit luminescence under infrared light

• Using the correct filters, these residues can be visualized and photographed

• Sodium Rhodizonate Test

• Chemical test for lead

• Griess Test

• Chemical test for nitrites

• While we most often look for GSR on the hands, skin and clothing…..be aware of its potential existence on other surfaces at a scene.

9

• In some cases, the absence of GSR can be just as important and telling…...

• Mechanical Test• Muzzle to target test

• Utilize gun in question and same ammunition

Section IIIProcessing the Shooting

Scene

General Considerations

• Usually a complex sequence involving multiple dynamics

• The processing of a shooting scene needs to include all of the requirements necessary to meet proper processing protocols

• Must pass through and include all aspects of a thorough crime scene investigation

• Additionally, must include the detailed information gathering necessary for analysis and reconstruction for shooting purposes

General Considerations• Safety ! ! !

• Firearms

• Biologicals

• Chemicals

• Utilize appropriate PPE

• Open minded and objective• Think logically about the possibility of illogical or

irrational thinking and/or actions/events

• No detail of a case can either be excluded outright or taken at face value

• Close minded and “tunnel vision”• Won’t allow you to see illogical actions or event

possibilities

General Considerations

• No one person has a monopoly on information or could possible have a complete understanding as to circumstances of a case

• Utilize necessary expertise and/or specialty disciplines as needed to guarantee the best possible forensic and investigative results

• The shooting crime scene is all about information and the information is all about the evidence

10

General Considerations

• A thorough investigation can be viewed as multiple layers of information superimposed upon each other to create a complete or near complete picture• No one layer is sufficiently reliable or complete

enough to give the type of clarity needed for an accurate picture

• This couldn’t be more true with shooting scene analysis and reconstruction

• You will walk down a potentially error filled path if in your analysis and reconstruction you consider the shooting within the vacuum of just the shooting

Recorded Notes and Observations

Photographic & Video Documentation

Evidence Search, Documentation and Collection

Sketches and Diagrams

Visible and Latent Print Examinations

Detailed Report, Findings and Reconstructions

Blood Pattern Documentation and Analysis

Statements, Interviews and Investigative Dialogue

Shooting & Flight Path Documentation and Analysis

Forensic/Scientific/Expert/ME Analysis

General Considerations

• Must pass through the same stages as any other crime scene processing• Arrival and walkthrough assessment

• Legal considerations

• Documentation

• Notes – extremely detailed!!!

• Photography/Video

• Measurements and Sketch/Diagram

• Evidence collection

• Specialized disciplines

• Shooting scene examination and processing is a “scene” within a scene

Section IVTerminology

Terminology of Shooting Analysis and Reconstruction

A compilation from three sources:

Lucien C. Haag, “Shooting Incident Reconstruction”

Edward E. Hueske, Practical Analysis and Reconstruction of Shooting Incidents

Dean H. Garrison, Jr., Practical Shooting Scene Investigation

• Cartridge• Single complete round of ammunition• Includes in it’s entirety the cartridge case (metal

or plastic), primer, powder charge and bullet/projectile

• Referred to as a shotshell (shotguns) and may have additional components

11

• Cartridge Case

• Container for all other components of the cartridge (Cartridge Casing/Shell Casing) exclusive of the bullet/projectile

• Fired Cartridge Case

• Cartridge case which has been discharged from a firearm which no longer has the bullet component

• Bullet• The projectile portion of a cartridge that emerges

from the barrel/muzzle and travels towards a target

• Core – portion of bullet beneath the jacket

• Jacket – metallic covering over the core

• Shotshells:

• Slug – single projectile component of a shotgun cartridge

• Pellet – roughly spherical projectile components of a shotgun cartridge

• Miscellaneous Components of Shotshell• Shot Cup – protects and encases the shot

• Shot Collar – plastic or paper insert surrounding the charge

• Wad – paper separator between the pellet/slug and charge

• Shotshell Buffer – granular material to occupy space and keep shot apart

12

• Bullet/Projectile/Slug/Pellet Descriptive Terms

• Intact – bullet/projectile in one whole piece

• Fragment – a piece of a bullet i.e. bullet fragment, jacket fragment, metal fragment

• Deformed – indicates bullet/projectile damaged usually from impact with a target surface

Bullet Exhibiting Evidence of Two Distinct Impacts

• Embedded – projectile/bullet stuck in or protruding from a target surface

• Projectile/bullet is also at the terminus of it’s flight path when embedded in a target surface

• Terminus – final resting place where the bullet/projectile ends up at the end of it’s flight path (final target surface)

-Can be at it’s terminuswithout being embedded

13

• Target• Object or surface (substrate) struck

by bullet/projectile

• Three general types:• Yielding – surface which gives way

or tends to bend or stretch upon application of force (wood, drywall, sheet metal)

• Frangible – surface

subject to crumbling

or breaking

upon application

of force (cinder blocks

bricks, pavers)

• Non-Yielding – surface

not significantly

affected upon

application of force

(stone, marble, heavy steel)

• Three general classes:• Fixed – an object, device or appliance that by design is

fastened or secured at a specific location not readily or easily capable of movement or articulation, i.e. walls, floors, ceilings, trees, telephone poles, radiators, sidewalks, pavement, etc.

• Moveable – an object, device or appliance that by design is capable of changing position or articulation, i.e. furniture, vehicles, people, too numerous to mention, etc.

• A moveable object can exist in two general ways:

• A moveable object with a defined range of motion, i.e. doors (residence/vehicle), windows (residence/vehicle), vehicle seats etc. within a scene

• A moveable object without a defined range of motion, i.e. capable of being in almost any position or location within a scene

• Stationary – an object, device or appliance that by design is considered moveable but at a specific point in time is not moving

Fixed, Moveable and Stationary Objects

• Reason for Importance – each class of objects brings different considerations and possibilities for their potential movement, range of movement or lack of movement to a shooting scene analysis and subsequent reconstruction

• If an object is capable of movement, that movement must be taken into consideration during a shooting scene analysis as the object may potentially be in one or more different positions or orientations at the time different shots are fired

• Flight Path• The path of a bullet/projectile in flight upon

impact

-Utilize flight path rods to illustrate

14

• Angle of Impact (Incidence)• The interior (acute) angle of the axis of an

impinging or intercepting bullet/projectile with a target surface (Incident angle) measured• To the vertical plane

• To the horizontal plane

• A complete description for the angle of impact requires a measurement to both the vertical and horizontal plane• Each of these has two components

• An angle component measured in approximate degrees

• A directionality component

• Will discuss in greater detail later in the presentation

• Defect

• Damage produced on a object/target as a result of a bullet/projectile impact event• Perforation Defect – bullet which passes completely through

the target

• Penetration Defect – bullet which enters but does not emerge from the target

Entrance Defect –location where a bullet/projectile first impacts and enters a target surface

Flight Path of Shot

Flight Path of Shot

Leading Edge – that portion of a defect produced by the initial contact between the bullet and target surface which produces a shoulder and/or impression

Flight Path of Shot

Flight Path of Shot

Leading Edge

Leading Edge –more difficult to determine due to the combination of two different target surface types and curvatures at the point of impact site

15

Flight Path of Shot

Flight Path of Shot

Leading EdgeShoulder

Leading EdgeShoulder

Leading EdgeShoulder

Flight Path of Shot

Leading EdgeShoulder

Flight Path of Shot

Flight Path of Shot

Leading EdgeShoulder

Leading EdgeShoulder

Pinch Point

Flight Path of Shot

Pinch Point- a small area of survivable paint that was pinched between the bullet’s initial contact point and the painted sheet metal surface- does not always occur- function of the quality of paint

and metal

Leading EdgeShoulder Flight Path of Shot

16

Leading EdgeShoulder Flight Path of Shot

• Exit Defect –location where a bullet/projectile emerges from a target surface

Corresponding Defect - damage which aligns and appears to be the result of a single bullet flight path

– May include new flight paths produced as a result of fragmentation

Sequential Photos

• Keyhole Defect – irregular shaped defect/damage which indicates the bullet has started to exhibit a tumbling action or has become deformed in shape

• The result of contact with or passing through an intermediate target

• Bullet Wipe – the discolored area on the immediate periphery of a bullet hole, caused by the transference of residues from the bearing surface of the bullet

• Can occur at any range so long as the bullet has not passed through some intermediate object

• Lead-In Mark – a visible, thin elongated deposition of bullet wipe transferred to a surface as a bullet first makes contact with that surface at a shallow impact angle

• Can assist in the determination of directionality

17

Bullet W

ipe on Lead-In Mark

Lead Splash

•Lead Splash – the production and dispersal of vaporized or fine particles of lead as a result of impact

- Dependent upon bullet design, nature of the surface struck and energy associated with the impact- Can assist in the determination of directionality

Direction

Ricochet Defect• Ricochet Defect – a change in angle and/or direction of a

bullet/projectile as a result of impact with a substrate without perforation or penetration (glancing rebound off a target surface)• Ricochet Mark/Crease – a two or three dimensional

defect dependent upon the type of surface/substrate• Skip, skid – shallow• Furrow, trench – deeper

• Chunk-out – causes a piece of the target to fly away

• Ricochet defect CAN have three potential angles:• Angle of Impact - the interior (acute) angle of the axis of

an impinging or intercepting bullet/projectile with a target surface

• Angle of Ricochet – angle of departure of a bullet/projectile as it leaves the substrate

• Angle of Deflection – lateral directional change of a ricocheting bullet/projectile from it’s original inbound line of travel (left or right on a horizontal surface/up or down on a vertical surface)

Ricochet Defect con’t• Critical Angle – angle at or below which a ricochet would

be expected for a given bullet/projectile and a given substrate

• Lead in Mark – at low incident angles the initial contact between the bullet and target surface produces a dark elongated and elliptical transfer of material

• Boat Wave Fractures – some types of paint on sheet metal surfaces fracture in a characteristic and reproducible way as the metal yields to the bullets advance

• Ricochet Defects are a type of defect often encountered at shooting scenes and can take on many forms and appearances

• The more complicated the interaction between the bullet and the target surface = Greater care must be taken in interpreting directionality and angles

Boat Wave Fractures or Christmas Tree Effect Point In the Direction of Shot Origin

Sharks Teeth Point in theDirection of Shot Origin

FLIGHT PATH of SHOT

Lead in Mark

18

Angle of Impact Damage Angle of Ricochet Damage

Angle of D

eflectionTransitionArea

Flight Path of Shot

Flight Path of Shot Flight Path of Shot

Leading EdgeShoulder

Leading EdgeShoulder

Leading EdgeShoulder

Lead Splash

Angle of ImpactDamage

Angle of RicochetDamage

TransitionArea

Angle of D

eflection

Lead In Mark

Lead Out mark

Flight Path of Shot

19

LEADING EDGE WITHCOPPER JACKET

FRAGMENT

DIRECTION?

Lead-InMark

Impact Mark

Angle of Incidence~14° +/- 5°

Ricochet Mark

Angle of Ricochet~17° +/- 5°

Angle ofDeflection~8° +/- 3°

DIRECTION?

Direction?1, 2 or 3 Shots?

Faint Elliptical ShapedLeading Edge

20

Direction? Direction?

DIRECTION?

DIRECTION?

Ricochetdefectscan occuron anysurfaceas longas the impactangle is at orbelow thecritical angle.

Ricochet Defect In Windshield

The Equivalent of a Ricochet on a Humanis Referred to as a Graze Wound

21

Initial Flight Path andDirection of Shot

As Bullet Strikes Knuckle ItFragments

Jacket ContinuesOn PerforatingThe Skin

Lead Continues OnCreating Graze Woundon Back of Hand

Partially Bent andSlightly Twisted WristProduces Void

Lead Continues OnCreating a 2nd GrazeWound on Wrist

- Flight Path Without

Perforation/Penetration

Through Fabric/Foam

- Equivalent of a “Graze”

Wound on a Human

Direction?

Spall Defect – projectile/bullet causes damage upon impact to a target surface without going through or emerging

SPALL

22

A Word About Location and Position

• Secondary Projectile - a chunk-out piece of the target is set into motion • Chunk-out Piece – piece/fragment of target

• Secondary Projectile Defect – a chunk-out piece is set into motion and produces it’s own damage• May establish it’s own flight path

Need to establish both location and position for defects

Need to document through photographs, notes/charts/logs etc.– Location - describes the defect as it relates to the target

surface as an object in it’s entirety

– Position - describes the defect as it relates to it’s specific site on the target surface

Location and Position Examples

• Room

• Location - north wall of the kitchen

• Position ~ 34” up from the floor and ~ 18 from the west corner

• Vehicle

• Location - driver’s side front door

• Position ~ 6” down from the lower window line and ~ 14” back from the front leading edge

• Object

• Location – front face of center back cushion of sofa

• Position ~ 8” up from bottom edge and ~ 10” from left edge

• Equipment for Determining Angles of Impact and Flight Path• Flight Path Rod - any plastic, wooden or metal rod placed into

a defect to help determine flight path and/or angle of impact of the responsible bullet/projectile/shot

• Protractor – used to determine the angle to the vertical plane

• Angle Finder – used to determine the angle to the horizontal plane

• Cone – used to stabilize the placement/position of a flight path rod (try to limit use as it prevents the flight path rod from resting directly on the leading edge)

• Laser Adapter – colored laser light beam tool used to illustrate the continuation of a flight path into the environment (attaches to a flight path rod)

• Flight Path Bracket – used to help set and maintain flight path rod in place while obtaining Angle of Impact measurements

• Distance/Range of Fire• Contact – muzzle of firearm in direct contact

with target surface• Complete

• Partial

• Near Contact – muzzle of firearm in extremely close proximity to the target surface, but not touching

• Intermediate – muzzle to target surface distance sufficient to produce powder stippling or deposition of gunpowder particles

• Distant – muzzle to target surface beyond a distance which gunpowder particles can travel and deposit on the target surface

• French Fry

• Compressed and punched out section of foam padding creating the shape and appearance of a french fry

23

French Fry AnalysisFrom Evidence Technology Magazine

November/December, 2009by

John Louis LarsenLarsen Forensics, Inc., Consulting

Glen Ellyn, IL

• When a bullet perforates a material such as the headrest of a car seat or some piece of heavy, upholstered furniture (such as a sofa or recliner) the bullet passing through the soft material will punch out a section of foam that can look a lot like a French fry

• The darkened end is where the bullet made the initial contact with the foam and produces a slight discoloration

• Useful indicators for:

• can help determine how many rounds may have struck an object

• cause the investigator to take a second look at the scene to make sure that his interpretation of the event is accurate

• accounting tool to make sure all bullet strikes have been accounted for, successfully noted and documented

• Do not travel far from their source and are usually observed within a foot or two of the host object

• Not evidence to be collected, but are physical clues to indicate a target surface has been potentially impacted by a bullet

• Glass• Plate – flat glass having an extremely clear smooth

surface lacking any special treatments or construction

• Tempered – glass with stress built in during manufacture to prevent sharp edges from occurring upon breakage, i.e. side and back car windows

• Laminate – glass consisting of two sheets of plate glass cemented around a piece of plastic/vinyl laminate, i.e. windshield

• Glass Fracture• Damage to a glass target surface by a

projectile/bullet• Concentric – circular fracture of glass surrounding a

point of impact or defect

• Radial – linear or near linear fractures radiating outward from the point of impact or defect (Lines of Fracture)

• Conchoidal – fractures visible on the edges of broken glass at the point of impact or defect that allow direction of force determination

• Sympathetic – fractures produced as a result of indirect contact of a bullet to a target surface directly adjacent to glass

• Pulverized/Diced – tiny nondescript fragments of glass in tempered glass

• Will go into much greater detail later in the presentation

Section VShooting Incident Specific

Analysis and Data Collection

24

Goals and Objectives

• Search, documentation and collection of physical evidence which assists in the determination as to the facts and circumstances of the case

• Evaluation of firearms and firearms related evidence to assist in the determination of facts and circumstances

• Determination of the location/position of shooters and targets

• Determination of the sequence of events

• Caution!! – as this can be potentially damaging process

• Multi-disciplinary approach

• Greatest accuracy will occur with scene in original condition

• Need to make a determination as to what can and needs to be done at scene

• Need to make a determination as to what is best accomplished in a controlled environment

I. Shot Accounting

• Reconcile the number of fired cartridges cases, bullets, bullet defects in targets• Objects

• People (wounds)

• Missed shots???

• Every effort should be made to resolve prior to leaving scene• Extremely helpful if some info is available during processing

• Types of weapons and remaining fired and unfired cartridges

• Magazine capacities

• Any reloading??

• Requires dialogue with other detectives, ME, persons involved

• Always evaluate for accuracy

II. Glass Fracture Analysis

• Glass behaves in a predictable way with reproducible results exhibiting certain characteristics• Can determine the location/position of projectile

strikes

• Can determine the sequence of projectile strikes

• Can determine the direction of projectile strikes• Entrance side usually relatively smooth

• Exit side usually cratered or exhibits beveling

• Documentation and preservation is crucial for accuracy of results

Types of Glass Fractures

• All produced as a result of impact and dispersal of KE in the glass

• Appearance dependent upon the type of glass

• Radial Fracture – linear or near linear fracture extending outward from the point of impact

• Concentric Fracture – fracture forming in an approximately circular pattern around the point of impact

• Conchoidal Fracture – fracture that does not follow any natural planes, produced by the shearing effect of bullet contact with the glass

• Occurs in brittle materials like glass

• Responsible for the production of the beveling, coning or crater feature useful in determination of direction of force

• Dice Fracture – nondescript fractures in tempered glass resulting in irregular pieces of glass which is a design feature of tempered glass

Directionof

Penetration

A projectile hole is

inevitably wider at the

exit side

bsapp.com

25

EXITENTRANCE

• Same characteristic is observable in flat bone i.e. skull

Directionof

Perforation and Resultant Fractures

Concentric fractures caused by secondary

stress to glass

Radial fractures caused by initial stress to glass

bsapp.com

Fractures

Co

ncen

tric

Radial

bsapp.com

RADIALFRACTURES

CONCHOIDALFRACTURES

CONCENTRICFRACTURES

CONCHOIDALFRACTURES

EDGE OF BULLET IMPACT SITE

26

• The type, number and characteristics of the fractures produced is dependent upon:• Type/nature of the projectile• Amount of forced released/absorbed by the glass• Type/nature of the glass itself

• Tempered Glass• Radial fracture lines are only produced as a result of the

first impact of a bullet to the glass• Can determine the location/position of the first bullet

impact• Presence of a complete or partial intact defect hole

• Can also allow for a determination of directionality (beveling)

• Through the utilization of fracture lines

• Radial fractures will transition to non descript dicing as one gets further from the point of impact

• Subsequent bullet impacts to already compromised glass will “knock out” pre-existing fractured glass• Will not produce any new radial/concentric fractures

• First impact can be identified while subsequent impacts will need additional information/evidence

Low Energy Impact

High EnergyImpact

27

Determination of Position in Tempered Glass

• The fracture lines created when a projectile impacts tempered glass results in the radial fractures and pulverized/dicing effect previously described

• These fracture lines radiate in a linear or near linear manner and are visible in the glass

• Tracing of a number of these “reliable” lines can establish an area of convergence indicative of where the position of the initial impact point

• Subsequent impacts to already compromised tempered glass will not result in any useful or measurable characteristics and/or information

Area of Convergence

Area of Convergence

Area of Convergence

INITIAL SHOT THROUGH GLASSAS DETERMINED BY RADIAL AND

CONCENTRIC FRACTURE LINEPRODUCTION, CONVERGENCE AND

CONCHOIDAL BEVELING

SECOND SHOT THROUGHALREADY COMPROMISED

TEMPERED GLASS

SECOND SHOT THROUGH ALREADY COMPROMISEDTEMPERED GLASS AS DETERMINED BY – NO RADIAL AND CONCENTRIC

FRACTURES AND NO CONCHOIDAL BEVELING

28

Documentation and the setting of the radial fracture string lines at the scene when the window was still somewhat intact allows for the positioning of the defect later during processing when the window glass is no longer present or has been compromised

So are there times we can sequence shots with tempered glass?

Defect ADirection ?Sequence ?

Defect BDirection ?Sequence ?

Outside Cab Looking In

Defect ADirection ?Sequence ?

Defect BDirection ?Sequence ?

Inside Cab Looking Out

What Are We Seeing Here?• Questions to ask:

• Tempered glass?

• Presence of beveling?

• Convergence of radial fracture lines?

• Questions to ask:– Tempered glass? YES

– Presence of beveling? NO

– Convergence of radial fracture lines? YES

29

FORCESUFFICIENT TO PRODUCE

TEMPERED GLASS FEATURESBUT NO PERFORATION JUST

IMPACT – GLASSJUST FELL OUT BELOW

POINT OF IMPACT

What Are We Seeing Here?• Questions to ask:

• Laminate glass?

• Presence of beveling?

• Convergence of radial fracture lines?

• Questions to ask:– Laminate glass? YES

– Presence of beveling? NO

– Convergence of radial fracture lines? YES

FORCE SUFFICIENT TO PRODUCELAMINATE GLASS FEATURESBUT NO PERFORATION JUST

IMPACT – GLASSJUST FELL OUT BELOW

POINT OF IMPACT

Laminate Glass Bullet Impact

• Produce radial, concentric and conchoidal fractures (beveling)

• No dicing – Can sustain multiple impacts with the production of these three fractures with each impact.

30

1

2

Sequencing of Defects in Glass

A fracture line terminates at a

pre-existing line of fracture

Allows for the opportunity to determine sequence of defect penetrations:

- requires at least one true reliable fracture line from one defect intersecting one true reliable fracture line from another defect in the same “plane” of glass

bsapp.com bsapp.com

31

Laminate GlassNot Just in Windshields

• Many vehicle models produced after 2012 have laminate glass in the side windows of front and some rear doors.

• Laminate side windows will behave just as a windshield:

• Multiple impacts without the expected features associated with tempered glass.

• Production of radial, concentric and conchoidal fractures.

• Possibility of sequencing.

• Remember - a window IS a moveable object. This potential for movement must be taken into consideration just like any other moveable object with respect to position at the time of any one shot!

Entrance defect on interiorfront door panel

WindowPosition At

Time ofProcessing

Window inLowered Position

at Timeof Shot -

Defects Align

Shooter Position and Deflection Through Laminate Glass

An Investigation of the Effects of Laminated Glass on Bullet Deflection

From the Journal of Forensic IdentificationVol. 63, No. 3, May/June 2013

byGary Wilgus, James Bryan White and

Julia BerryOhio Bureau of Criminal Investigation

London, Ohio

• Previous research suggests a consistent bullet deflection of approx. 1 to 5 degrees downward

• Study was undertaken to determine whether enough bullet deflection occurs after perforating laminated glass to change the calculated location of the shooter vs. the know location of the shooter

32

• The deflection values for each gun and bullet type do not support a consistent downward deflection as proposed by previous research

• Bullet deflection occurred in every direction in no specific pattern (up, down, right and left)

• Deflection even varied among bullets fired using the same gun and ammunition

• All bullets fired with the exception of two fell within the reasonable uncertainty level of -5 to +5 degrees

• Conclusion: Bullet deflection through laminated glass does not appear to significantly affect the calculated location of the shooter and can continue to reliably be utilized to calculate an approximate shooter location

Important Glass Considerations• Can be EXTREMELY fragile and fleeting

• Good chance it is probably already not in original condition

• Must preserve and document from this point on• Must establish position/location utilizing reference

marks on fixed aspects of the target

• Important to photograph, make notes, take measurements etc.

• May be a task requiring action before other aspects of scene processing

• Use clear/near transparent tape or wide adhesive strips to preserve• Manufacturing or after market tinting can act to assist

in preservation

• Use “Crash Wrap” film to preserve• Use trace evidence adhesive scene pads• Use transparent adhesive spray to preserve

ADHESIVE MATERIALi.e. tape, film, etc.

SPRAY ADHESIVE

• Preserve and collect glass intact in the frame to be utilized as a control if necessary for comparison purposes to determine interior/exterior surface of the glass fragments not present in the frame• Label/designate interior and exterior surface of

control sections of glass

• Analysis of features of the glass such as mineral composition, float side, presence of dirt/dust, tinting, blood, any other foreign matter, etc. can give valuable information for glass found both in and out of the frame

• Size of the hole and diameter of the crater cannot be used to reliably predict the size of the projectile

• Awareness of the value of glass as trace evidence, i.e. on subjects clothing etc. may show their presence at time of the shooting

III. Ejection Pattern AnalysisThe Importance of Careful Interpretation

of Shell Casing Ejection PatternsFrom the Journal of Forensic IdentificationVol. 55, No. 6, November/December 2005*

byErin Sims

Larry BarksdaleLincoln Police Department

Lincoln, NE

Fired Cartridge Case Ejection Patterns From Semi-Automatic Firearms

From the Investigative Sciences JournalVol. 2, No. 3, November 2010

byWilliam J. Lewinski, Ph.D., William B. Hudson, Ph.D., David Karwoski

and Christa J. Redmann

33

• Both studies found a number of variables either individually or collectively play a role

• Limitations/considerations:

• Type of firearm, design and condition

• Type of ammunition

• Physical orientation of the firearm

• Physical orientation of the shooter

• Movement of shooter and/or firearm

• Grip factors, i.e. loosely or tightly held

• Movement of target

• Ground surface type

• After deposition factors – disturbed or undisturbed (all or some in original location)

• Conclusion: All of the above variables must be considered before any effort is made to establish the location of a shooter based solely on the location of fired cartridge casings

• CAN provide information as to the position and location of shooter(s)

• Location of fired cartridges alone is not a reliable indicator of the location of the shooter

• When used in conjunction with other evidence “can” be helpful and/or supportive of other findings

H&K .45 Caliber H&K .45 Caliber

.22 Caliber

IV. Impact Marks from Ejected Cartridge Casings

From the Journal of Forensic IdentificationVol. 54, No. 5, September/October 2004*

byJ. K. PoormanT. F. Spring

US Air Force Office of Special InvestigationsWashington, DC

• Ejected ammunition casings “can” leave characteristic impact marks on wallboard or other impressionable surfaces

• The identification and documentation of such marks at shooting scenes, evaluated with other physical evidence and information, could help in reconstructing events • close confines of a hallway, stairwell, or small room

34

Impact Marks from Experiments

Impact Mark on Wall andFired Cartridge Casefrom Actual Scene

V. Defect Analysis

• Remember defects can appear• on any type of target surface

• Wood, sheetrock, metal, fabric, glass, clothing, skin/bone, plastic etc.

• of any type of target

• Wall, floor, ceiling, furniture, vehicle, human

• All require the same meticulous attention and processing

• Can give information as to

• Directionality to a vertical plane• Angle of Impact measured to the vertical plane of a

target surface

• Directionality to a horizontal plane• Angle of Impact measured to the horizontal plane of a

target surface

• Convergence of flight paths can give an approximate area for position of shooter

• Limitations:

• Movement of shooter and/or weapon and/or

• Movement of target

• Nature of the target surface being struck• Flat/Concave/Convex

• Integrity/Reliability as a template

• Make-up/Composition

• Describe

• Photograph

• Measure as to location and position on target surface

• Measure as to size and shape of the defect

• Chemical Testing if necessary to aid in establishing a potential defect or not• Detection of the lead and/or copper component of a bullet

So Just When You Thought…

• Ammunition advances that potentially change some of the key elements/features used to identify initial bullet impacts to a target surface

• Polymer Coated Bullets

• Lead or jacketed bullet coated with a baked on polymer coating

• Polymer Composition Bullets

• Injection molding technology uses a copper powder and high tensile strength nylon epoxy resin polymer

PolyCase Ammunition– RNP – Round Nose Precision

– ARX – Advanced Rotation eXtreme

35

• Designed for RH twist barrels but tests have shown just as effective in a LH

• Fluted nose produces no stability issues

• Transfers force/energy in a new way

• Rotationally

• Laterally

• Low recoil and larger temporary cavities of any bullet of the same caliber

• Less bullet mass allows for higher velocities

• Not a frangible round

• Hollow-Points rely on expansion effect to transfer terminal energy

Section VIAngles of Impact,

Flight Path Analysisand Convergence

Determining Angle of Impact (Incidence) Flight Path Rod Method

• Always given as an approximate angle in degrees• Always measured and described in relationship to the

surface impacted and to the target• Horizontal plane and associated directionality

• Vertical plane and associated directionality

• Equipment• Flight Path Rods/Probes

• Cones (Not recommended – use with caution)

• Protractor (Vertical Plane)

• Angle Finder (Horizontal Plane)

• Smart Level

• Involves the physical placement of the rods and measuring against the target surface

• Not to be confused with flight path analysis• Need first two reliable defect points along the same flight

path for accuracy• Initial impact defect and next defect in sequence

Target

1st Defect inTarget Surface

2nd Defect inTarget

2nd Defect inTarget

1st Defect inTarget Surface

3rd Defect inTarget

Correct Flight Path

Incorrect Flight Path

1st Defect(Bal-19)

2nd Defect(Bal-19A)

36

Measurement to the Vertical Plane (Use Protractor)

ANGLEOF IMPACT

LeftorBack

Angle of ImpactTo the Vertical Plane

(Looking Vertically Down on a Wall)

Rightor

Front

TARGET SURFACE

VERTICALPLANE

ViewLooking

Down

Measurement to the Horizontal Plane (Use Angle Finder)

Angle of ImpactTo the Horizontal Plane

(Looking at the Edge of a Wall)

TAR

GE

T S

UR

FAC

E

ANGLEOF IMPACT

Horizontal Plane

Side View

FP Rod Methodology1. Identify the first reliable initial impact defect on the target

(Defect #1)2. Identify the second sequential reliable impact defect on the

target (Defect #1A)3. Identify the leading edge of Defect #14. Set the flight path rod so it rests on the leading edge of

Defect #1 and the rod tip contacts Defect #1A5. Utilizing the side of the rod nearest the leading edge,

measure the angle of impact to the vertical plane using the protractor and determine directionality

1. Always given and recorded as an approximate (~) angle in degrees with direction

6. Utilizing the angle finder measure the angle of impact to the horizontal plane and determine directionality

1. Always given and recorded as an approximate (~) angle in degrees with direction

7. Record all measurements using, notes, charts, diagrams, etc.• Do not photograph the protractor or angle finder to document the

measurements

WRONG!

RIGHT!

DRYWALLTARGET

SURFACE

37

WRONG!

WRONG!Approx. (~) 56˚ Angle of Impact to the Vertical Plane (Left to

Right or West to East)

WRONG!Approx. (~) 53˚ Angle of Impact to the Vertical Plane (Left to

Right or West to East)

NORTH WALL

RIGHT!

WRONG!Approx. (~) 37˚ Angle of Impact to the Vertical Plane (Left to

Right or West to East)

RIGHT!Approx. (~) 34˚ Angle of Impact to the Vertical Plane (Left to

Right or West to East)

NORTH WALL

RIGHT!

RIGHT!Approx. (~) 4˚

Angle of Impact to the Horizontal

Plane (Down)

VEHICLEAUTOBODY

SHEET METAL

TARGETSURFACE

WRONG!

RIGHT!

WRONG!

WRONG!Approx. (~) 42˚ Angle of Impact to the Vertical Plane (Left to

Right or Back to Front)

WRONG!Approx. (~) 45˚ Angle of Impact to the Vertical Plane (Left to

Right or Back to Front)

EXTERIORPASSENGER SIDE

REAR DOOR

EXTERIORPASSENGER SIDE

REAR DOOR

RIGHT!

WRONG!Approx. (~) 36˚ Angle of Impact to the Vertical Plane (Left to

Right or Back to Front)

RIGHT!Approx. (~) 33˚ Angle of Impact to the Vertical Plane (Left to

Right or Back to Front)

38

RIGHT! RIGHT!Approx. (~) 7˚

Angle of Impact to the Horizontal

Plane (Down)

Use of Cone –Angle measurement is taken along the center line of the flight path rod

• Study was undertaken to compare the known angle of impact of bullets with the angle of impact utilizing the flight path rod method

• Determined the absolute value difference between the examiner measurement and the true known value to be approx. 1.7 degrees

• Employing a standard deviation of:

• +/- 1.7 degrees yielded an ~68% confidence level with the true known value

• +/- 3.4 degrees yielded an ~95% confidence level with the true known value

• +/- 5.1 degrees yielded an ~99+% confidence level with the true known value

The Accuracy and Precision of Trajectory Measurements

From the AFTE JournalVol. 40, No. 2, Spring, 2008

byMichael Haag, Albuquerque Police Department, Albuquerque, NM

• Critical to these results was the proper placement of the flight path rod with attention given to the leading edge aspect of the defect and contact with the true reliable 2nd

point in sequence

• Shallower angles with longer leading edges gave more accurate results when the flight path rod was resting snuggly within the leading edge

• A consideration also with ricochet defects

• Potentially eliminates the need to reach a 2nd point

• Considerations which decrease accuracy:

• Shallow angle impacts (aligning with a second point)

• Perforation of heavier substrates (capable of causing alteration of flight path, rendering 2nd point in sequence not reliable/valid)

• Previously destabilized bullet impact

The Three Point Requirement• In addition to the two reliable point requirement for

the FP Rod Method, a third reliable point becomes necessary when the target object is moveable or capable of articulating in more than one position• Necessary to establish the proper location and position of

the target object at the time of the shot.

• Necessary to establish the proper location and position of the target object in order to obtain an accurate angle of impact at the time of the shot.

• Absent the third point, it may not be possible to establish the angle of impact with any degree of certainty.

• Just as in bloodstain, when an object is moveable, great care has to be taken before deciding any analysis will lead to a reliable conclusion.

• Can potentially provide a “range” but caution must be used and it must be clearly stated that the flight path can exist along any line within that “range” and to what plane or planes the range is in relation to.

Determining Angle of Impact (Incidence)

Trigonometric Method• Same scientific principles which apply to

calculating the angle of impact as a blood droplet impacts a virtually flat target surface can be utilized to determine the angle of impact of a bullet/projectile into virtually flat substrate and/or object surfaces

• Requires the measurement of the length and width of the defect mark

39

Can be used in conjunction with the rod method

Can be used when only one defect point is present

Always given as an approximate angle in degrees

Always measured and described in relationship to the surface impacted and to the target– If you are doing Trig on a vertical surface, then the

measured and calculated angle is to the vertical plane

– If you are doing Trig on a horizontal surface, then the measured and calculated angle is to the horizontal plane

– Still requires a directionality component

Equipment Accurate measuring device (ruler, caliper)

Scientific calculator

Width- 3

Length- 6

Step One:Divide Width by Length3/6 = 0.5

Step Two:Take Inverse Sin of 0.5 = 30 degrees

Half-Length Method of Ellipse Estimation

• Suggested method to utilize due to the destructive nature of a bullet impact mark

• Steps:• (1) Along the center line axis of the defect, trace the 

defect to the point at which the mark first becomes the widest

• This is where the width of the defect is measured

• (2) Measure back from point (1) to the leading edge and this becomes the half‐length measurement of the ellipse

• Double the half‐length measurement (2) and apply the width‐to‐length ratio mathematical calculation

Width 9mmLength 11mm = 0.82

Inverse sin 0.82= ~ 55 degrees

Using trig

Width 9mm

Length = 2 x 5.5mm

~ 53 DegreesUsing FPR

Width 9mm

Length = 2 x 12mm

Width 9mm

Length 24mm= 0.37

Inverse sin 0.37= ~ 22 degrees

Using trig

Note: the more irregular thedeformity of the defect, the more difficult to establish the correct margins which can lead to a greater opportunity forerror/discrepancy

~ 19 DegreesUsing FPR

40

11mm

12mm

Width = 12mmLength =22mm

= 0.54

Inverse sin 0.54= ~33 degrees

Using trig

~ 44 DegreesUsing FPR

So Why The Difference ??• TRIG Method = ~ 33 degrees

• FP Rod Method = ~ 44 degrees

• The behavior of the sheet metal target surface and the subsequent “folding back” of the sheet metal due to the force and energy during impact and perforation give an inaccurate appearance for damage and the resultant ellipse produced by the bullet

• As a result the width is much larger than that of the actual and true damage produced by the bullet by itself had the metal not “folded back”

• Consequently this also changes the resultant measurement for the length

• The ability to observe this difference will vary and may not be able to be determined and as such the ability to use the trigonometric method may not be possible with any degree of certainty or reliability depending upon the target surfaces ability to be a reliable template

Ellipse ProducedVisible Damagew. Folding Back

Actual Ellipse ProducedFrom Just Bullet Damage

New Length7mm

New Width9mm

So Now if We Use the New Width and the New Length

Width = 9mmLength =14mm = 0.64

Inverse sin 0.64= ~40 degrees

This creates a much more accurate picture of the damageproduced by the bullet and as such the Trig Methodresult of ~40 degrees is closer in agreement to theFlight Path Rod Method of ~44 degrees

Remember!

• The Trig Method gives the angle of impact to the plane the trig is being measured/performed on:

• If doing trig on a horizontal plane, then the angle measured and calculated is to the horizontal plane.

• If doing trig on a vertical plane, then the angle measured and calculated is to the vertical plane.

• So how do we get the other “half” of the angle of impact?

41

~ 13 degreesDown to the

Horizontal Plane

Trig on a Vertical SurfaceCreating the Horizontal Plane

~ 13 degreesDown to the

Horizontal Plane

~ 13 degreesDown to the

Horizontal Plane

Trig on a Horizontal SurfaceCreating the Vertical Plane

42

43

Reliability of Impact Angles Utilizing the Trigonometric Method

Angle of Impact Determination from Bullet HolesFrom the Journal of Forensic Identification

Vol. 63, No. 3, May/June 2013by

Kenton S. Wong, Forensic Analytical Sciences, Inc., Hayward, CAJohn Jacobson, Federal Bureau of Alcohol, Tobacco, Firearms and Explosives, Walnut Creek,

CA

• Study was undertaken to compare the known angle of impact of bullets fired into flat media (sheetrock, wood and vehicle sheet metal) with the calculated angle of impact utilizing the trigonometric method

• General Rule with Blood: The accuracy of determination of the impact angle for bloodstains is within +/- 5 to 7 degrees• The collapse and deposition of the blood

droplet as it impacts the target surface occurs in a very predictable fashion based on the cohesive forces of the blood drop

• For less elliptically shaped blood droplets (more circular in shape) the error rate rises dramatically

• Depending on the target media, the production of the bullet hole caused by bullet impact may result in tearing and destruction of the target media rendering that target surface much less reliable for accurate length and width measurements as compared to blood

• For bullet marks just as with blood, the less elliptically shaped bullet holes (more circular in shape) produced greater error rates• Test bullet holes produced between 70 degrees to

90 degrees were virtually indistinguishable from one another

• Angle of Impact determinations were approximately within 10 degrees of the known impact angle

• As such the use of the Trigonometric Method must be evaluated with respect to reliability for each mark as being sufficient for determining the Angle of Impact and general position of a shooter

• Don’t have the luxury of “sampling and averaging” as in determining bloodstain angles of impact

44

ShotgunTrigonometric

Method(Example 12 pellet cartridge)

• Minimum Diameter of Ellipse (d) is related to range of fire (distance) to target

• As (d) increases, the distance from muzzle to target increases

• Maximum Diameter of Ellipse (D) is a function of the angle of impact

• As (D) increases (i.e. the more elliptical the shape), the lower the angle of impact

d = MinimumDiameter of Ellipse

D = Maximum Diameter of Ellipse

Step One:Divide Minimum Diameter of Ellipse (d) by Maximum Diameter of Ellipse (D)

Step Two:Inverse sin

Flyers(Excluded)

W=105mm

L=220mm

L=75mm

W=55mm

Flight Path Analysis• Takes Two Forms

• With respect to the target• The process by which defects are associated along a

single flight path

• The process by which bullets/fragments etc. are associated to a specific flight path

• With respect to the determination of the location/origin of the shot (position of muzzle)• Extension of a flight path into the environment• Never exclusively a function of this analysis

• Requires other types of physical evidence to narrow the area

• Always referred to as a range (area of convergence)

• Flight path rods transition from a measuring device used to determine angle of impact to an illustrative tool used to show the travel of a bullet after initial impact

• Target within a target i.e. person standing in a room, seated in a vehicle etc.

• Location will not just be determined based upon flight path analysis

• Equipment

• Rods

• Strings

• Lasers

• Smart Level

• Scales/identifiers

• CAD software programs

• Utilize scales/identifiers to create a visual record of the defects and associated flight path( i.e. JPM-BD#1, JPM-BD#1A, JPM-BD#1B, JPM-BD#2, JPM#3 etc.) for documentation purposes

• NOT meant to be a shot sequencing tool

Flight Path Convergence/Origin

• Area of Convergence – the space in two dimensions to which the directionality of bullet flight paths can be traced to determine the location of the muzzle.

Wall with Bullet Defects (Elevation View)

• Area of Origin – the space in three dimensions to which the bullet flight paths can be utilized to determine the location of the muzzle (origin of the shot).

Wall with Bullet Defects (Floor Plan View)

Wall with Bullet Defects(Profile View)

Area of Origin(Relative to theVertical Plane)

Area of Origin(Relative to theHorizontal Plane)

45

Considerations & Limitations

• For bloodstains determining area of origin for is based upon a single source event producing a multiplicity of individual stains capable of being traced back to an area of origin.

• For shootings there is no guarantee that the bullet holes were fired by a stationary shooter.

• As a result:

• Tracing back of flight paths may create false areas of convergence and thus a false area of origin.

• Each bullet could have been fired anywhere along each flight path line, not necessarily within the area where the flight paths converge.

• Unlike bloodstains where their area of origin establishes a de facto area for the bloodstain producing event.

• Shots which created the bullet defects may have been fired from different positions that created an area of origin by mere coincidence.

• MUST be independent corroborating evidence to support area of origin for flight paths.

• Might be able to narrow potential areas of origin by what types of independent corroborating evidence:

• Presence or absence of GSR

• Unreasonable muzzle height

• Location of fired cartridge casings

• Area of Origin:

• Assumes a static shooter for the firing location of two or more shots (shooter not moving).

• Assumes a static target for the firing of two or more shots (target not moving).

• Assumes no intervening targets between the muzzle and the final target surface.

• May result in an erroneous angle of impact as a result of passing through an intermediate target which could alter its flight path and now produce an angle of impact in a scene target that is not representative of the shot that produced it.

• MUST! MUST!

• Consider the possibility of movement of the shooter and or target before finding an area of origin for two or more shots.

• Have independent corroborating evidence to support establishing an area of origin.

• The more the better!

Flight Path vs. Wound Track• When we speak of flight path in the human body we use

the term wound track

• Wound track is a determination made by the medical examiner as to the “flight path” of a bullet as it passes through the body and encounters:• Skin

• Tissue

• Organs

• Bones

• Wound tracks can terminate inside the body (penetration) or pass completely through (perforation)

• Medical examiner will use some of the same terms in describing the movement of a bullet through the body

• Just as a bullet can fragment when it encounters targets and surfaces at the scene, the same can happen in the body creating multiple wound tracks

46

47

Presentation of Wound Track Findings from Autopsy Report

• How you choose to do it:

• Provides an essential part of your understanding of a shooting and wound track

• Provides an essential part of someone else’s understanding of a shooting and wound track

• Provides the same information as an angle of impact, directionality and flight path through an object

1. Can use narrative description in your report

2. Can use CAD drawing software to supplement (1)

3. Can use POSER 3D software to supplement (1) and/or (2)

Shooting Example

• Narrative Example for GSW#1: A penetrating entrance gunshot wound is present in the right temple. Upon perforating the skull the bullet fragmented creating a secondary wound track resulting in a partial exit above the right ear. The flight path of this wound track is front to back, tangential and slightly downward. Copper jacket and lead fragments were recovered associated with both of these wound tracks (Referred to as Gunshot Wound #1 in the autopsy report).

• CAD Software Example for GSW#1

48

• 3D Software Example for GSW#1

Entry GSW#1

Partial ExitGSW#1

• Narrative Example for GSW#4: A penetrating entrance gunshot wound is present in the right back. The bullet terminates within the musculature of front left abdominal wall. The flight path of this wound track is back to front, right to left and downward. A copper jacketed lead projectile is recovered associated with this wound track (Referred to as Gunshot Wound #4 in the autopsy report

• CAD Software Example for GSW#4

• 3D Software Example for GSW#4

Entry GSW#4

GSW#4TerminusWithin theAbdomen

Entry GSW#4

GSW#4TerminusWithin theAbdomen

49

• Narrative Example for GSW#5: A penetrating entrance gunshot wound is present in the right underarm. The bullet terminates in the lower left chest. The flight path of this wound track is back to front, right to left and downward. A copper jacketed projectile is recovered associated with this wound track (Referred to as Gunshot Wound #5 in the autopsy report)

• CAD Software Example for GSW#5

• 3D Software Example for GSW#5

Entry GSW#5

GSW#5TerminusWithin the

Lower Left Chest

Entry GSW#5

GSW#5TerminusWithin theLower Left

Chest

CAD Software Example for GSW#4 and GSW#5

• 3D Software Example for GSW#4 and GSW#5

Entry GSW#5

Entry GSW#4

Entry GSW#5

Entry GSW#4 3D Software Illustration for GSW#4 and GSW#5

50

Section VIIDocumentation and Evidence Collection

Documentation• The collection of all relevant information and data

through the use of:• Notes/Logs/Charts

• Pertaining to the crime scene(s)*

• Specific to the shooting analysis

• Photographic Documentation

• Pertaining to the crime scene(s)*

• Specific to the shooting analysis

• Measurements

• Pertaining to the crime scene(s)*

• Specific to the shooting analysis

• *Remembering that the “scene” can include any physical location, object/target, vehicle, weapon, person, i.e. any and all components which may have played a role in the events that transpired

Notes/Logs/Charts• Description of the general scene

• Description of location and position of significant scene aspects

• Description of location and position of defects and secondary defects along a flight path (Defect Chart)

• Description of location and position of firearms and related physical evidence documented and recovered at the shooting scene (Evidence Log)

• Description of location and position of trace, biological, pattern, transfer, impression, etc. related physical evidence documented and recovered at the shooting scene (Evidence Log)

Photography• Documentation Quality of all aspects of the

shooting scene (without/with a scale/identifiers)

• Examination Quality of specific elements within the shooting scene (without/with a scale/identifiers)

• Include• Firearms (condition and configuration),

bullets/projectiles, cartridges, cartridge cases, fragments, magazines, wadding, etc.

• Bullet defects (perforations, penetrations, entrance, exit and ricochet defects etc.)

• Flight paths, ejection patterns, glass fractures etc.

• Flight path rods, strings, laser light etc.

• Must depict in an organized manner the location, position, relationship and inter-relationship of all of the elements

51

• Photograph:• Defects at 90 degree angle to the target

surface (without/with-scale/identifier)

• Defects along a flight path at 90 degree angle to the target surface (without/with-scale/identifier)

• Flight path rods perpendicular to the target surface which will depict the impact to the vertical plane

• Flight path rods parallel to the target surface which will depict the impact to the horizontal plane

• Before anything is done in the way of evidence collection – be sure it has been documented (ongoing process)

ProperScale

AlignmentNO

YES

ProperScale

AlignmentNO

YES

52

Measurements/Sketches• Record:

• Location and position of defects relative to a target surface (placement)

• Angle of impact to the vertical plane and direction

• Angle of impact to the horizontal plane and direction

• Angle of ricochet and direction

• Angle of deflection and direction

• Length and width of a defect

• Used for production/inclusion of a diagram (more detailed depiction)

• Utilize charts, diagrams, etc. to record same

Target Surface Analysis and Subsequent Documentation

• Once all critical aspects of the scene have been thoroughly documented and recorded in their original as found condition, the target surface can be utilized in the analysis and documentation process and preserved photographically

53

Evidence Collection• Follow all protocols for proper collection

• Remember potential for multiple pathways/types/categories of analysis

• One item = one package• Prevent contamination/cross contamination

• Prevent damage/deterioration/alteration

• Use appropriate packaging/container• Label with appropriate information

• Seal and mark• NO markings directly on evidence (tags, package

etc.)

• Maintain integrity and security (chain of custody)

• Firearms• SAFETY !!!!

• Document complete condition• Loaded

• Safety

• Position of hammer

• Chamber and cartridge

• Magazine and cartridges

• Serial #

• Blood, hairs, fibers, (intact or collect), prints\

• Revolver

• Cylinder position, location of fired and live cartridges

• Make safe

• Package (gun box)

54

• Bullets/Projectiles/Shot/Fragments• Document condition

• Document location and position

• Bio, trace etc. (intact/collect)

• Caution in handling and retrieving (tool marks)

• Fired bullets may be difficult to recover at crime scenes due to being embedded in walls, ceilings, door frames, window frames or other materials.

• Only rubber coated or taped tools should be used to recover them so as to prevent damage.

• It is preferred to remove section of target surface containing bullet for further analysis.

• Bullets should not be marked or damaged

• Appropriate package (individually)

• Cartridges• Same considerations as above

• Remember!!!

• Evidence can be found almost anywhere.

• As such, one can never be too thorough when conducting a search and processing a shooting scene

• Remember!!!

• Bullet Impacts can be found almost anywhere.

55

• Ammunition• All ammunition present at scene, in possession of

suspect etc. should be seized as evidence

• For subsequent analysis of range of fire, pellet patterns or other testing

Section VIIIVehicles

Special Considerations(Vehicles)

• Measure and record vehicle dimensions• General (length, height, width etc.)

• Specific (door and window openings etc.)

• Measurement

• Manufacturer

• Measure and record vehicle angles of inclination if perforated by bullets (windshield, rear window, etc.)

• Curvature requires establishment of vertical and horizontal planes for consistency of measurement

• Measurements taken to establish the location/position of defects need to be referenced to the vehicle AND the surface upon which the vehicle rests (ground).

• Angled surfaces must be taken into consideration (i.e. a 25 degree downward angle into a 40 degree angled windshield)

• Condition of vehicle as it relates to these measurements must also be taken into consideration (1 wheel up on a curb, flat tire(s), damage)• When examined

• When fired upon

• Insert rods/probes and determine angular measurements to the vertical and horizontal plane

• Document flight paths in notes, logs, charts, and through identifiers, photographic views (perpendicular, profile, overhead etc.• Hidden defects

• Prepare sketches, diagrams

• Vehicle Stationary at time of or during part of the shooting sequence

• Vehicle moving at time of or during part of the shooting sequence

• Damage to vehicle before, during or after the shooting

56

• Utilize available software applications to assist with documentation, to aid in obtaining an understanding and to help visualize investigative findings/results.

Squaring Off TechniqueFrom the Journal of Forensic Identification

Vol. 59, No. 1, January/February 2009by

Brian VivonaMichael Gaspari

Elk Grove Village Police DepartmentElk Grove, IL

• Utilize graph paper, CAD software or field squares to measure angles to constant baselines

• Provides consistent reference points for documentation and reconstruction

• Transposes the angle measured directly to the target surface to the angle measured directly to the baseline

• Standardizes all of the measurements to the target

• Can allow for clearer illustrations for documentation and/or analysis purposes

~ 18° DownAngle

~ 13° DownAngle

57

~ 5° DownAngle

~ 5° DownAngle

~ 106° DownAngle

~ 24° DownAngle

~ 14° F to R

~ 25° F to R

~ 45° R to F

~ 49° R to F

~ 27° R to F

~ 27° R to F

Section IXReconstruction

Reconstruction

• Formulation of the best theory of a set of events in a case based on consideration of all available evidence and information

• The process of putting together the evidence and information available with the objective of understanding the nature and sequence of events that create it

• Application of established scientific principles through the use of scientific methods, physical evidence and deductive reasoning, and their interrelationships to gain explicit knowledge of the series of events surrounding a shooting event or incident

Reconstruction Objectives• Potential Event Information

• Range from firearm to target

• Position/orientation of firearm at time of discharge

• Position/orientation of target at time of discharge

• Position of shooter at the time of discharge

• # of shots

• Sequence of shots

• Intervening objects/materials between firearm and target [effect on projectile(s)]

• Flight paths of projectile

• Requires analysis of physical evidence

• Requires other evidence, i.e. blood spatter, gunshot residues etc.

• May involve some participant information• Persons involved

• Degree of involvement

• Point of view

• Hand dominance

• Description of actions

• Role of perception

• ***Evaluate for reliability***

58

• Know when to say “when”

• Ask for help

• While you may not be the one doing the final shooting reconstruction….• Does not relieve you of the obligation of collecting all of the

relevant data and information

• Your results documented and preserved allow the accuracy of any findings to be evaluated later

• Utilize all tools at your disposal

• Limited in your conclusions by the amount of specialized training you have had in reconstruction and experience in the field

• Requires unbiased, objective and clear analytical thinking

• Application of scientific method to evaluate any number of explanations of one or more events in a shooting incident

• If more than one scenario for a given set of facts exists, then an objective reconstruction must include those scenarios

• Applied Science- application of methods and techniques whose roots are drawn from other scientific disciplines, i.e. physics, mathematics, ballistics, trigonometry, chemistry etc.

Compounding Complexity• The more complex a shooting scene is = the more

complex and difficult the analysis and reconstruction

• The more targets and the movement of one or more of those targets

• The more shooters and the movement of one or more of those shooters

• The more shots fired

• The movement of key elements from their original positions at the time of the shooting

• Any one or combination of the above will make any reconstruction substantially more difficult to complete, as such we may end up with partial reconstructions of only certain aspects off the overall shooting investigation

• In it’s most simple form:

• Two shots fired may not be twice as hard to reconstruct as one shot, but rather 4 times as hard

• Four shots fired may not be four times as hard to reconstruct as one shot, or twice as hard as two shots but rather eight times as hard

• “If, in your analysis, you do not consider reasonable alternative explanations of an event, then what you are doing is not science.” Dr. Ed Blake, forensic serologist

• By way of an over simplified but illustrative example…………

Scenario #1: Moving Shooter & Moving Firearm (Fixed Wall)

59

Scenario #2: Stationary Shooter – Moving Firearm (Fixed Wall)

• The angles of impact for the three defects will be the same for Scenario #1 and Scenario #2

• The actuality of the events that produced the three defects can be Scenario #1, Scenario #2 or a combination of both

• A conclusion as to the actual events and the sequence of the shots (whether it will be possible to even reach such a conclusion) will depend upon other information if available……not just the defect marks and angles of impact!!!

When confronted with two or more reasonable scenarios that could explain the

same analysis and findings……

• Must view and consider those scenarios through the lens of ALL available evidence

• Must present all the scenarios in reconstruction report to remain and convey objectivity

• Given a certain set of evidential facts and investigative data, one scenario may be:

• more plausible than another

• more consistent with the findings than another

• If either is the case - need to clearly demonstrate, explain and illustrate exactly why one scenario is more plausible/consistent

Case Study• Boyfriend dumps girlfriend

• Girlfriend retrieves revolver from 2nd floor bedroom

• Boyfriend sustains:

• One graze wound to back of neck

• Two perforating wounds to the back which exit the chest

• One perforating wound to the right triceps which exits the bicep

• One graze wound to the back of the right hand by the thumb

• At Issue:

• Defense claims subject was advancing up stairway towards girlfriend in a threatening manner and she fired in self defense, then boyfriend turned away to head down steps

• Prosecution claims subject was fleeing from girlfriend down stairway and she fired out of anger

60

61

Section XReports and Testimony

• Reports will contain all aspects of your recorded actions• Photographs• Evidence Logs• Measurements• Diagrams• Charts

• Written component will consist of three parts• Observations/recording of facts• Findings during analysis• Interpretations/Conclusions leading to reconstruction

(partial or complete)

• Utilize software to help determine and/or illustrate your findings/conclusions

• Remain consistent in your descriptions and terminology used to describe evidence, flight paths, events, etc.• Important consideration not only at time report is written,

but in your recording of information and data at scene/evidence

• Consistent style and format required to clearly show and explain observations and findings

• Do not overstate your findings

• Make conclusions commensurate with your knowledge, training and experience

• Conclusions MUST be objectively based upon documented supportable observations

• Need to know and be able to describe exactly what it is that you do

• Need to know and be able to describe the scientific/technical basis or foundation behind your discipline

• Need to know and be able to describe exactly how you perform your tasks

• Need to know and be able to describe exactly what your results or conclusions are and what they mean AND/OR what they don’t mean

• Obligation as a professional scientist or investigator is to find the truth or facts of a case

• Obligation as a professional witness is to make sure the truth and facts are clearly told, explained and understood

Shooting Incident Format –Sample Report Format

• Report exists as a report within a report but needs to:• Stand alone with respect to the observations and

analysis concerned with just the shooting aspect of the crime scene investigation

• Integrate with other aspects of the crime scene investigation to support any findings and conclusions leading to the reconstruction

• Three Sections (suggestion)• Observations/recording of facts (Matters not in dispute)• Findings during examination/analysis• Interpretations/Conclusions leading to reconstruction

(partial or complete) which answers the questions of what transpired (Matters in dispute)

ExampleFindings During

Examination and Analysis

62

EXAMPLE

• Position and Location

• …an apparent bullet defect (DEF#1), consistent with a single gunshot located on the front passenger side door ~ 10 3/8” from the door’s rear edge, ~ 6” below the door’s lower window edge and ~ 32-1/2” from the ground

• Defect Description

• …the entrance defect perforated the front passenger side door, was elliptical in shape, with paint missing around its margins and measured ~ 14 mm (width) by ~ 30 mm (length)

• Angle of Incidence

• …the bullet impacted the front passenger side door ~ 35° to the vertical plane (front to rear) and ~ 5° to the horizontal plane (downward)

• Flight Path

• …the bullet perforated the passenger side door (DEF#1), exited through the interior vinyl panel just above the door handle (DEF#1A), entered the front fabric face of the back cushion of the passenger side front seat (DEF#1B) and terminated within the foam of this back seat cushion

EXAMPLE

• Position and Location• …an apparent pellet group defect (DEF#2),

consistent with a single shotgun shot located on the rear passenger side quarter panel the approximate center of which measured ~ 19-3/8” from the left rear corner, ~ 1-1/2” above a strip of decorative trim and ~ 30-1/4” from the ground

• Defect Description• … the entrance defect in its entirety consisted of

nine (9) circular shaped holes ( ~ ¼” in diameter) with paint missing around their margins, was roughly circular in shape, measured ~ 86 mm (width) by 114 mm (length) and perforated/penetrated the rear passenger side quarter panel

• Angle of Incidence

• …the pellets impacted the rear passenger side quarter panel ~ 87° to the vertical plane (front to rear) and ~ 8° to the horizontal plane (downward)

• Flight Path

• …six pellets perforated the rear passenger side quarter panel (DEF#2) and terminated within the confines of the trunk space. Three pellets penetrated the rear passenger side quarter panel (DEF#2) and terminated within the confines of the quarter panel

EXAMPLE

• Position and Location • …an apparent bullet defect (DEF#3), consistent

with a single gunshot was located on the south wall of the living room ~ 72-1/4” from the southwest corner and ~ 56” from the floor

• Defect Description• …the entrance defect perforated the sheet rock

wall, was roughly circular in shape and measured ~ 5 mm (width) by ~ 6 mm (length)

• Angle of Incidence• …the bullet impacted the sheetrock of the south

living room wall at ~ 84° to the vertical plane (right to left) and ~ 2° to the horizontal plane (downward)

• Flight Path

• …the bullet perforated the sheetrock of the south wall of the living room (DEF#3), penetrated the sheetrock of the south wall of the adjoining den (DEF#3A) and terminated in the insulation within the den’s south wall

63

Taking It One Step Further

Reconstruction Findings – FBI Shooting

64

Reconstruction Findings – FBI Shooting Example

• Finding #1: BAL#1 is consistent with a projectile whose flight path strikes the front driver’s side door of the vehicle at approximately a 68 degree angle (rear to front) to the vertical plane of the open door and at approximately a 6 degree down angle to the horizontal plane while the door is open to an angle of approximately 54 degrees. (Refer to Exhibit A, D, E and F)

• Finding #2: BAL#2 is consistent with a projectile whose flight path strikes the front driver’s side door of the vehicle at approximately a 57 degree angle (rear to front) to the vertical plane of the open door and at approximately a 2 degree down angle to the horizontal plane while the door is open to an angle of approximately 68 degrees. (Refer to Exhibit B, D, G and H)

• Finding #3: The projectile flight paths of BAL#1 and BAL#2 and resultant defects indicate that the driver’s side front door of the vehicle was in two different open positions as each of the two projectiles impacted the door.

65

• Finding #4: Taking into account the two different positions of the open front driver’s side door of the vehicle (Finding #3), the projectile flight path for BAL#2 aligns with the projectile flight path for BAL#3 and this association is consistent with the projectile flight paths of BAL#2 and BAL#3 originating from one and the same shot with the door open at approximately 68 degrees.

• Finding #5: Two shots struck the vehicle and the projectile flight paths for each resulted in the recovery of two projectile fragments from within the interior

passenger compartment of the vehicle.

• One projectile fragment (item FBI#7) can be associated with projectile flight path BAL#1.

• One projectile fragment (item FBI#1) can be associated with projectile flight path BAL#2/BAL#3.

• Finding #6 - The sequence of the two shots cannot be determined with any degree of certainty

• Finding #7: The incidence angles to the horizontal plane for projectile flight paths BAL#1 and BAL#2 converge at distance of approximately 138 inches (11 ft. 6 in.) from the points of impact on the front driver’s side door of the vehicle. (Refer to Exhibit I)

Area of Origin

• Finding #8: The incidence angles to the vertical plane for projectile flight paths BAL#1 and BAL#2 converge at distance of approximately 138 inches (11 ft. 6 in. ) from the points of impact on the front driver’s side door of the vehicle. Arrival at this point of convergence is dependent upon consideration being given to the two different and distinct positions of the open front driver’s side door of the vehicle at the time each of these two shots were discharged from the weapon and struck the vehicle. (Refer to Exhibit J)

66

• Is to take complex topics and create investigative tutorials to explain these topics in a clear and simple manner

• Is to remember that the eventual “audience” of our investigative efforts and findings is not just our investigative peers but rather a jury of lay people

Bottom Line

QUESTIONS ?

• References• Practical Analysis and Reconstruction of Shooting

Incidents by Edward E. Hueske, CRC Press, Taylor & Francis Group, LLC, 2006

• Shooting Incident Reconstruction by Lucien C. Haag, Elsevier Academic Press, 2006

• Practical Shooting Scene Investigation by Dean H. Garrison, Jr., Universal Publishers, 2003

• Practical Crime Scene Analysis and Reconstruction by Ross M. Gardner and Tom Bevel, CRC Press, Taylor & Francis Group, LLC, 2010 (Mathew Noedel, Shooting Scene Processing and Reconstruction)

• Crime Reconstruction by W. Jerry Chisum and Brent Turvey, Elsevier Academic Press, 2006 (Bruce Moran, Shooting Incident Reconstruction)

Contact Information

• Jim Molinaro

• Cell # (908)625-0958

• jmolinaro@highlandsforensics.com

• Howie Ryan

• Cell # (732)558-5886

• hryan@highlandsforensics.com