The Crime SceneThe Crime Scene

Catalyst 10/1/13Catalyst 10/1/13

Question: Differentiate between class Question: Differentiate between class and individual evidence.and individual evidence.

Answer: Answer:

What do you think happened? Why?

Locard’s PrincipleLocard’s Principle

Dr. Edmond LocardDr. Edmond Locard Director of the world’s first forensic Director of the world’s first forensic

lab in Francelab in France Came up with the idea that when a Came up with the idea that when a

person comes into contact with an person comes into contact with an object or another person, a object or another person, a cross-cross-transfertransfer of physical evidence of physical evidence can can occur.occur.

2 Main Types of Evidence2 Main Types of Evidence

1-Direct1-Direct 2-Circumstantial2-Circumstantial

EvidenceEvidence

Main types (continued)Main types (continued) 1-Direct evidence1-Direct evidence 2-Circumstantial evidence2-Circumstantial evidence

Trace evidenceTrace evidenceClass evidenceClass evidence Individual evidenceIndividual evidence

DirectDirect Evidence Evidence Consists of Consists of firsthandfirsthand observationsobservations In court, this evidence involves testimony by In court, this evidence involves testimony by

a witness about what that witness personally a witness about what that witness personally saw, heard, or did. (NO intermediary, directly saw, heard, or did. (NO intermediary, directly from example to the investigator)from example to the investigator)

Examples:Examples: Eyewitness accountsEyewitness accounts Police dashboard videoPolice dashboard video ConfessionsConfessions

CircumstantialCircumstantial Evidence Evidence

IndirectIndirect evidence that can be used evidence that can be used to imply fact but does not directly to imply fact but does not directly prove itprove it

May provide a May provide a linklink between a crime between a crime scene and a suspectscene and a suspect

OnlyOnly suspect and victim actually see suspect and victim actually see it left at crime sceneit left at crime scene

Can be physical or biologicalCan be physical or biological

CircumstantialCircumstantial Evidence (cont) Evidence (cont)

ExamplesExamples:: Finding a suspect’s gun at the site of a Finding a suspect’s gun at the site of a

shootingshooting Biological evidence:Biological evidence:

Body fluids, hair, plant parts, and natural Body fluids, hair, plant parts, and natural fibersfibers

Physical evidence:Physical evidence: Fingerprints, footprints, shoe impressions, Fingerprints, footprints, shoe impressions,

tire impressions, bullets, and tool markstire impressions, bullets, and tool marks

TraceTrace Evidence Evidence (type of Circumstantial)(type of Circumstantial)

Type of Circumstantial evidenceType of Circumstantial evidence Physical transfer of materialPhysical transfer of material ExamplesExamples::

HairHair FingerprintsFingerprints SoilSoil BloodBlood KleenexKleenex FiberFiber GlassGlass Paint chipsPaint chips

ClassClass Evidence Evidence (type of Circumstantial)(type of Circumstantial) Narrows an identity to a group of Narrows an identity to a group of

persons or thingspersons or things CannotCannot specify a single person specify a single person Only excludes people that do not fit Only excludes people that do not fit

the categorythe category Examples:Examples:

Blood typesBlood types Hair colorHair color Common fibersCommon fibers Shoe printsShoe prints

IndividualIndividual Evidence Evidence (type of Circumstantial)(type of Circumstantial)

Narrows identity to a single person or Narrows identity to a single person or thingthing

Examples:Examples: DNADNA Complete fingerprints(not partials)Complete fingerprints(not partials) Tool marksTool marks Anything torn or broken and left at the Anything torn or broken and left at the

scenescene

Catalyst 10/2/13Catalyst 10/2/13

Question: What is the difference Question: What is the difference between circumstantial and direct between circumstantial and direct evidence?evidence?

Answer:Answer:

Forensic Activity-ROBBERY!Forensic Activity-ROBBERY!A large appliance store was robbed, but no forced entry was apparent. A tab from a beverage can was found by one of the outside doors, causing investigators to assume that it may have been used to wedge the door for later access. The next day, the driver of a vehicle was pulled over for a minor traffic violation. In the car were a number of empty soda cans, all with their tabs removed.

Answer in your groups!Answer in your groups! Can you verify that whoever robbed the store worked

there? Explain your answer. Did the robber have some connection to anyone that

worked there? Explain your answer. Can the tab found at the crime scene be associated with

the empty soda cans in the suspect’s car? Why or why not?

How would you go about trying to individualize the tab to the can?

How strong of a case can you, the forensic investigator, establish against the suspect? Explain your answer.

What kind of evidence is the tab; class or individual? Explain your answer.

What additional evidence could be collected from the tab that was left at the crime scene to strengthen this case? Explain how your answer would help the prosecution.

5 S’s of Crime Scene 5 S’s of Crime Scene InvestigationInvestigation

Securing the sceneSecuring the scene Separating the witnessesSeparating the witnesses Scanning the sceneScanning the scene Sketching and photograph the sceneSketching and photograph the scene Searching and collecting of evidenceSearching and collecting of evidence

1-Securing the Scene1-Securing the Scene

The most important job at a crime The most important job at a crime scenescene

Performed by the first officer at the Performed by the first officer at the scene, called the scene, called the first responderfirst responder

Safety of all individuals in first prioritySafety of all individuals in first priority Preservation of evidence is secondPreservation of evidence is second Finally record the sceneFinally record the scene

2-Separate the witnesses2-Separate the witnesses

Separation prevents them talking to Separation prevents them talking to each othereach other

Each witness will be asked about the Each witness will be asked about the crime scene and what they observedcrime scene and what they observed

3-Scan the Scene3-Scan the Scene

Determine if and where photos Determine if and where photos should be takenshould be taken

Determine if there may be a Determine if there may be a secondary crime scenesecondary crime scene Person killed at a party (primary scene)Person killed at a party (primary scene) Dumped in a lake (secondary scene)Dumped in a lake (secondary scene)

4-Sketching the Scene4-Sketching the Scene

First is a Rough Sketch done at the sceneFirst is a Rough Sketch done at the scene Must be Must be accurateaccurate and and to scaleto scale Note body, evidence, doorways, windows, Note body, evidence, doorways, windows,

walls, trees, cars, and movable objectswalls, trees, cars, and movable objects Distances should be measured and Distances should be measured and

recordedrecorded Case number, date, location, and time Case number, date, location, and time

should also appear on the sketch should also appear on the sketch

Rough SketchRough Sketch

QuickTime™ and a decompressor

are needed to see this picture.

FinalFinal Sketch Sketch

Usually done by a computerUsually done by a computer Presented in courtPresented in court

Photographing the Photographing the Crime SceneCrime Scene

Photograph:Photograph: All evidenceAll evidence Doors and Doors and

windowswindows Anything out of Anything out of

the ordinarythe ordinary

5-Searching and Collecting 5-Searching and Collecting EvidenceEvidence

Must be properly packaged, sealed, and Must be properly packaged, sealed, and labeledlabeled

Dry evidence Dry evidence - placed in a paper bindle, - placed in a paper bindle, put into a plastic bag, sealed with tape, put into a plastic bag, sealed with tape, labeledlabeled

Wet evidence Wet evidence - placed in a paper bag to - placed in a paper bag to allow drying, then treated like dry allow drying, then treated like dry evidenceevidence

When bag is sealed, person must sign When bag is sealed, person must sign their name across the sealtheir name across the seal

Making a Making a paper bindlepaper bindle

Fold the paper into thirds both Fold the paper into thirds both directions so you end up with 9 directions so you end up with 9 rectanglesrectangles

Place your evidence in the middle Place your evidence in the middle and fold paper around itand fold paper around it

Do you have any further questions Do you have any further questions on how to create a paper bindle?on how to create a paper bindle?

Collecting EvidenceCollecting Evidence

Evidence LabelEvidence Label

Chain of CustodyChain of Custody

Must be Must be attachedattached to evidence to evidence containercontainer

Starts with person who Starts with person who findsfinds evidence evidence The next person to use or analyze the The next person to use or analyze the

evidence must fill out a labelevidence must fill out a label Ensures evidence is handled Ensures evidence is handled

correctlycorrectly If it is not handled correctly, can be If it is not handled correctly, can be

traced to who’s responsibletraced to who’s responsible

Crime Scene ReconstructionCrime Scene Reconstruction

Crime scene reconstruction Crime scene reconstruction involves: involves: forming a hypothesis of the forming a hypothesis of the

sequence of events from before sequence of events from before the crime was committedthe crime was committed

BEWARE of staged crimes (cover BEWARE of staged crimes (cover ups)ups)

Staged Crime ScenesStaged Crime Scenes

When the lab results When the lab results do not match do not match up up with the testimony of witnesses, it can with the testimony of witnesses, it can mean the crime was mean the crime was stagedstaged

Common examples include: Common examples include:

Staging a fire—to cover bankruptcy. Staging a fire—to cover bankruptcy. Staging a suicide—to cover a murder. Staging a suicide—to cover a murder. Staging a burglary—to collect insurance Staging a burglary—to collect insurance

money.money.

Staged Crime Scenes (cont)Staged Crime Scenes (cont)

To help determine whether a crime To help determine whether a crime scene was staged, consider: scene was staged, consider:

Whether the Whether the type of wound found type of wound found on on the victim matches the weapon employed. the victim matches the weapon employed.

Whether the wound could have been Whether the wound could have been easilyeasily self-inflicted. self-inflicted.

The The mood and actions mood and actions of the victim of the victim before the event. before the event.

The The mood and actions mood and actions of a suspect of a suspect before the event.before the event.