Unit 2- Crime Scene Investigation and Physical Evidence€¦ · Wallet Medium range shot Close up...

Unit 2- Evidence & Crime Scene

Investigation

CSI

“SPOT it” for Crime Scene

Investigating

1. Secure the Scene

2. Plan

3. Observe (notes/ photos/ sketch)

4. Take

Crime Scene Team

1) Police Officer (1st responding officer)

CSI TEAM

1) Team Lead

2) Photographer

3) Sketcher

4) Evidence Recorder/ Collector

5) Specialists (if needed)

Secure:

Duties of 1st responding Officer:

1) Check safety of scene (control physical threats)

2) Tend to the injured (call ambulance)

3) Separate witnesses and suspects

4) Secure the scene

• Exclude all unauthorized personnel

• Barricade boundary

Plan:

Lead CSI & Team Members:

• Cautiously walk through scene

– Establish safe route through scene (don’t disturb evidence)

– ID points of entry, attack, & exit

• Establish team roles

Observe

• Take photos

• Take notes

• Sketch scene

These help you “see” the scene

months/ years later

How open minded are you?

Can you change your perspective?

The Body Can Lead To An Object

……Sometimes The Object Isn’t A Weapon

Observing Evidence / Movement

Sketches• Used to supplement photos

• What to include:

– Dimensions of rooms, furniture, doors, & windows

– Evidence or things hosting the evidence (ex: table)

– Distances from two set points to the objects/ evidence

in the room

– Date, time, location, investigators names, case

identifier

– Legend/ Key, scale, compass orientation (North is at

top of page)

Rough Sketch

Final Sketch

2D vs. 3D

Types of Measurements

COORDINATE SYSTEM

3 ft.

5 ft.

TRIANGULATION20 ft.

17 ft.

BASELINE

10 ft.

7 ft.

GRID SYSTEM

1

2

3

4

A DB C

Notes• Date

• Time

• Description of location

• Weather

• Environment

• Description of the Scene with location of physical evidence

• Who recovered evidence & how it was packaged

Photograph and Videotape

Photos should include:

• Overall views of Scene

– looking into & out of scene

– Nearby areas

– Points of entry and exit

• Evidence Shots

– Medium range: evidence at

scene

– Close-ups: for details

• Rulers used in close-up photos

if size is important

Correct Photography

Background Photos / The Scene

360° Pictures

Wallet

Medium range shot Close up shot

Search

• Use a search pattern

(grid, line, zone)

• Use alternate light

sources

• Critical areas are checked

for trace evidence (hair,

fibers, bodily fluids,

fingerprints)

Shedding The Right Light Is Crucial

Side Lighting Top Lighting

Different Types Of Light

Fluorescent powder and UV light

Alternate

Light Source

Luminol

Trace Metal DetectionDifferent Metals Yield Different Colors

• brass/copper: purple

• steel/iron: black or dark purple

• aluminum: mottled yellow

• lead: tan or cream-colored

• galvanized iron (tin): bright yellow

• background: pale yellow

Aluminum

Lead

Copper

TMD

Pipe Test

Take Evidence• Wear gloves

• Collect fragile items first

• Package each item in a separate

container (appropriate for item)

with a label

• Obtain standards/ reference

samples for later comparison

• Maintain chain of custody

“Bagging and Tagging” is tough work

General Evidence Packaging Rules

1. Dry moist or wet evidence prior to packaging to prevent mold.

2. Allow for air circulation – USE PAPER

3. No plastic bags, sealed tubes, or jars -unless tissue/ tox samples

- arson evidence (no evaporating).

4. Biological items should be dried and kept in freezer

5. Package items separately.

6. Minimal handling - avoid talking/coughing over evidence.

Bagging & Tagging of Evidence

1) Tape seal package with initials before

leaving scene.

2) What goes on the evidence bag:

• type of case

• date

• location of collection

• item description

• police case number or identifier

• serial number or garment identifier

• collector's name and identifier information

• where item is being routed to for analysis

Package All Evidence In

envelopes, paper bags, or cardboard boxes

Guns

• Make safe

• Cartridges and cartridge casings

Ingenious packaging

More good packaging

Bad packaging…

Packaging the EvidenceOH NO,!!! Plastic

with wet material.

Chain of Custody- written record of

who has possession of evidence at all times.Starts with the CSI Evidence Storage Lab Attorney’s?

4 Requirements for Evidence to be

Admitted into Court:

1) It must be legally obtained (search warrant)

2) Must be relevant to the crime (material &

probative)

3) Witness must identify the item, identifying it’s

origin

4) Chain of Custody must be demonstrated

(every person that handled must also be

available to testify)

Search WarrantsPublished Casey Anthony search

warrant = a great example of what goes into a search warrant

• Need probable cause

• Need a detailed affidavit explaining why the authorities want to enter the home

• Explains what specific items they are interested in locating & where they want to look

• signature of a judge(http://blogs.discovery.com/criminal_report/files/casey_antho

ny_search_warrant.pdf )

Warrantless Searches

1) Emergent Situations- police may enter a building because

of emergency situation & evidence found can be used

(but they can’t come back again without warrant- Mincey Case)

2) Impending Loss of Evidence- person or situation might

cause evidence to be lost (ex: fire, person flushing drugs down

toilet)

3) Lawful Arrest- when a person is arrested any property in

his/her immediate control (vehicle, house) can be searched.

4) Consented Search- when person gives consent

Evidence

Types of Evidence

Direct Circumstantial (indirect)

Physical Biological

Individualized

Class

1st hand observations-

eyewitnesses, confession,

& videos

Used to imply a fact, but

does not directly prove it

Or

Individual vs. Class EvidenceIndividual Evidence

• Really high probability of being linked to one, unique source

• Ex:– Fingerprints

• 1 x 1060 = probability of 2 people having same fingerprint

– DNA

– Bullets

– Tire/ footwear patterns

– Tool marks

– Broken glass

Class Evidence

• Object has characteristics common to a group of similar objects

• Ex:– Hair

– Fibers

– Blue jeans

• Can increase the probability of class evidence by finding things that can make it unique:– Ex: stains, wear patterns

on jeans

Eyewitness Accounts• Juries heavily influenced by eyewitness

identifications.

• Lots of innocent people convicted b/c of faulty eyewitness accounts.

Some Issues: – types of questions asked by investigator

– type of crime

• Emotional arousal improves memory to a certain point

(Do you remember where you were when 9/11 happened?)

– time frame of questioning after event

– Cross racial identifications difficult

(watch: Eyewitness Testimony from 60 Mins)

4 Requirements for Evidence to be

Admitted into Court:

1) It must be legally obtained (search warrant)

-Even reference samples like DNA

2) Must be relevant to the crime (material &

probative)

3) Witness must identify the item, identifying it’s

origin

4) Chain of Custody must be demonstrated

(every person that handled must also be

available to testify)

Search WarrantsPublished Casey Anthony search

warrant = a great example of what goes into a search warrant

• Need probable cause

• Need a detailed affidavit explaining why the authorities want to enter the home

• Explains what specific items they are interested in locating & where they want to look

• signature of a judge(http://blogs.discovery.com/criminal_report/files/casey_antho

ny_search_warrant.pdf )

Warrantless Searches

1) Emergent Situations- police may enter a building because

of emergency situation & evidence found can be used

(but they can’t come back again without warrant- Mincey Case)

2) Impending Loss of Evidence- person or situation might

cause evidence to be lost (ex: fire, person flushing drugs down

toilet)

3) Lawful Arrest- when a person is arrested any property in

his/her immediate control (vehicle, house) can be searched.

4) Consented Search- when person gives consent

Questions from COURTExamples of questions asked by defense attorney’s:

1. “Why didn’t you collect that?”

2. “Why didn’t you take that photo?”

3. “Did you consider any other suspects?”

4. “Did you collect evidence to only make my client guilty?”

5. “Have you ever made a mistake – did you make one here?”

6. CSI effect

7. “I see that someone other than you collected this item – how can you prove to me that it was collected properly?”

8. “What if……..” scenarios

9. “How can you explain a finding on your report and there is nothing in your field notes to support that finding?”

10. “Are you an expert?”

11. “Why did you collect evidence that wasn’t analyzed?”

12. “Are you a robot for the state?”

13. “How do you know the evidence wasn’t tampered with during storage?”

Every move you make at a crime scene must be able to be explained - remember everything you do is for court and the jury.

Bullets & Fragments

Gopher Holes

Questioned Documents

Alterations & Obliterations

Can you tell what is obliterated?

A Blank Sheet Could Yield All This?

ESDA Film From 4th Sheet

Electrostatic Detection Apparatus

Reveals indented writing. The machine works by applying a charge to

the evidence and an opposite charge to acetate placed on top of the

evidence. The process transfers indented writing to the acetate.

-FBI

Mikrosil

• Cast prints

• Cast bullet holes in drywall

• Cast any impression in another

surface

Dental Stone? SMILE!