The Crime SceneThe Crime Scene

Locard’s Exchange PrincipleLocard’s Exchange PrincipleEvery contact leaves a trace!Every contact leaves a trace!

Whenever two objects come together they must Whenever two objects come together they must affect each other in some way. Something is affect each other in some way. Something is likely to be exchanged between them!likely to be exchanged between them!

Physical Evidence - anything that establishes a link between a crime and a person

Principle of IndividualityPrinciple of Individuality

Two objects may be indistinguishable, but no Two objects may be indistinguishable, but no two objects are ever identical. Things can be two objects are ever identical. Things can be

put into classes or even individualized in useful put into classes or even individualized in useful ways.ways.

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Frye vs. DaubertFrye vs. Daubert Daubert - “Does it work?”; Frye - “Do Daubert - “Does it work?”; Frye - “Do

scientists like and use it?”scientists like and use it?” FRE 702FRE 702 - If scientific, technical, or other If scientific, technical, or other

specialized knowledge will assist the trier of fact specialized knowledge will assist the trier of fact to understand the evidence or to determine a to understand the evidence or to determine a fact in issue, a witness qualified as an expert by fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or knowledge, skill, experience, training, or education, may testify thereto in the form of an education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is opinion or otherwise, if (1) the testimony is basedbased sufficiently upon facts or data, (2) the sufficiently upon facts or data, (2) the testimony is the product of reliable principles testimony is the product of reliable principles and methods, and (3) the witness has applied and methods, and (3) the witness has applied the principles and methods reliably to the facts the principles and methods reliably to the facts of the case.of the case.

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Search and SeizureSearch and Seizure Evidence at a Crime SceneEvidence at a Crime Scene 4th Ammendment to the Constitution4th Ammendment to the Constitution

““The right of the people to be secure in their The right of the people to be secure in their persons, houses, papers and effects, persons, houses, papers and effects, against unreasonable searches and against unreasonable searches and seizures, shall not be violated, and no seizures, shall not be violated, and no warrants shall issue, but upon probable warrants shall issue, but upon probable cause, supported by oath or affirmation, cause, supported by oath or affirmation, and particularly describing the place to be and particularly describing the place to be searched, and the persons or things to be searched, and the persons or things to be seized.”seized.”

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Search and SeizureSearch and Seizure Evidence at a Crime SceneEvidence at a Crime Scene 4th Ammendment to the Constitution4th Ammendment to the Constitution

““The right of the people to be secure in their The right of the people to be secure in their persons, houses, papers and effects, persons, houses, papers and effects, against against unreasonable searches and unreasonable searches and seizuresseizures, shall not be violated, and no , shall not be violated, and no warrants shall issue, but upon probable warrants shall issue, but upon probable cause, supported by oath or affirmation, cause, supported by oath or affirmation, and particularly describing the place to be and particularly describing the place to be searched, and the persons or things to be searched, and the persons or things to be seized.”seized.”

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Search and SeizureSearch and Seizure 4th Ammendment to the Constitution4th Ammendment to the Constitution

Allowances for Warrantless searches:Allowances for Warrantless searches: the existence of an emergency.the existence of an emergency. The need to prevent the immediate destruction The need to prevent the immediate destruction

of evidence.of evidence. A search of a person or property within the A search of a person or property within the

immediate control of the person provided it is immediate control of the person provided it is made incident to a lawful arrest.made incident to a lawful arrest.

A search made by consent of the person A search made by consent of the person involved.involved.

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Collection of Evidence - Collection of Evidence - Legal PrecedentLegal Precedent

MINCEY v. ARIZONA (U.S. Supreme Court, 1978) MINCEY v. ARIZONA (U.S. Supreme Court, 1978) Drug bust that went wrong and an undercover police Drug bust that went wrong and an undercover police

officer was killed.officer was killed. Police spent 4 days searching and seizing evidencePolice spent 4 days searching and seizing evidence Mincey arrested and convicted.Mincey arrested and convicted. Supreme Court ruled evidence collected was Supreme Court ruled evidence collected was

inadmissible because it was not from a proper search inadmissible because it was not from a proper search and seizure.and seizure.

Evidence taken without proper authority is probably not Evidence taken without proper authority is probably not legally admissible. legally admissible.

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Collection of Evidence - Collection of Evidence - Legal PrecedentLegal Precedent

Michigan v. Tyler (U.S. Supreme Court, 1978) Michigan v. Tyler (U.S. Supreme Court, 1978) Building destroyed by fire was put out in early AM.Building destroyed by fire was put out in early AM. Building left unsecured until 8 AM when a preliminary search Building left unsecured until 8 AM when a preliminary search

was done (for cause of fire).was done (for cause of fire). Subsequent searches (at 4, 7, and 25 days) removed additional Subsequent searches (at 4, 7, and 25 days) removed additional

evidence.evidence. Tyler convicted of arson.Tyler convicted of arson. Supreme Court:Supreme Court:

“…“…entry to fight a fire requires no warrant, and that once in entry to fight a fire requires no warrant, and that once in the building, officials may remain there for a reasonable time the building, officials may remain there for a reasonable time to investigate the cause of the blaze. Thereafter, additional to investigate the cause of the blaze. Thereafter, additional entries to investigate the cause of the fire must be made entries to investigate the cause of the fire must be made pursuant to the warrant procedures”pursuant to the warrant procedures”

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Physical EvidencePhysical Evidence Must be recognized at crime scene.Must be recognized at crime scene.

What relates to the crime and what What relates to the crime and what doesn’t.doesn’t.

Must be properly collected, Must be properly collected, preserved and controlled - from preserved and controlled - from massive to microscopicmassive to microscopic

Only aids in investigations (evidence Only aids in investigations (evidence doesn’t solve crimes by itself)doesn’t solve crimes by itself)

www.crime-scene-investigator.netwww.crime-scene-investigator.net

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Steps Taken at a Crime SceneSteps Taken at a Crime Scene

Secure and Isolate the scene.Secure and Isolate the scene. Render medical help and arrest suspects Render medical help and arrest suspects

(if needed)(if needed) Preserve and protect evidence (isolate Preserve and protect evidence (isolate

area)area) Exclude unauthorized personnelExclude unauthorized personnel Designate Officer in Charge (with authority)Designate Officer in Charge (with authority) Establish boundariesEstablish boundaries Document siteDocument site

Collection of EvidenceCollection of Evidence

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Team Leader Team Leader Photographer and Photographic Log Photographer and Photographic Log

RecorderRecorder Sketch Preparer Sketch Preparer Evidence Recorder/Evidence Recovery Evidence Recorder/Evidence Recovery

Personnel Personnel Specialists Specialists

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Team Leader Team Leader

Assume control and accessAssume control and access Determine search pattern and assignmentsDetermine search pattern and assignments Coordinate with groups involvedCoordinate with groups involved Continuously evaluate workContinuously evaluate work Release crime sceneRelease crime scene

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Evidence TeamEvidence Team Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities

Photographer and Photographic Log RecorderPhotographer and Photographic Log Recorder Photograph entire scene (before and after entered)Photograph entire scene (before and after entered) Photograph victim, crowd, vehiclesPhotograph victim, crowd, vehicles Photograph evidence before it’s moved (including Photograph evidence before it’s moved (including

fingerprints, casts, etc.)fingerprints, casts, etc.) Photograph evidence both in wide view (position at Photograph evidence both in wide view (position at

scene) and close-up (with scale)scene) and close-up (with scale) Possible use of video recording (does not replace still Possible use of video recording (does not replace still

photographyphotography Prepare photographic logPrepare photographic log

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Capture Crime SceneCapture Crime Scene

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Wide angle lenses are used to Wide angle lenses are used to distort the truth or emphasis itdistort the truth or emphasis it

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Details preservedDetails preserved

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Sketch PreparerSketch Preparer

Diagram area of scene (incl. orientation)Diagram area of scene (incl. orientation) Rough sketch - accurate dimensions, orientation Rough sketch - accurate dimensions, orientation

and location of evidence (from a fixed point)and location of evidence (from a fixed point) Finished sketch - aesthetic appearance (usually Finished sketch - aesthetic appearance (usually

done later sometime w/ CAD)done later sometime w/ CAD) Set forth major items of evidence on sketch (with Set forth major items of evidence on sketch (with

scale)scale) Make measurements (double check)Make measurements (double check)

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Sketch Preparer Sketch Preparer Rough Sketch

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Sketch Preparer Sketch Preparer

Finished Sketches

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Sketch Preparer Sketch Preparer

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Evidence Recorder/Evidence Recovery Evidence Recorder/Evidence Recovery

PersonnelPersonnel Have evidence photographed/sketched Have evidence photographed/sketched

before collectionbefore collection Describe evidence and location on containerDescribe evidence and location on container Package evidencePackage evidence Maintain chain of custody and evidence log Maintain chain of custody and evidence log Ensure proper safety of collection (e.g., Ensure proper safety of collection (e.g.,

infectious materials)infectious materials)

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Evidence TeamEvidence Team

Personnel Duties and ResponsibilitiesPersonnel Duties and Responsibilities Specialists Specialists

May include:May include: AnthropologistAnthropologist Blood expertBlood expert Bomb technicinBomb technicin CriminalistCriminalist EngineerEngineer EntomologistEntomologist Medical examinerMedical examiner OdontologistOdontologist SurveyorSurveyor Etc.Etc.

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Crime Scene SearchesCrime Scene Searches

Thorough and SystematicThorough and Systematic Unbiased and not overlook any Unbiased and not overlook any

relevant evidencerelevant evidence Depends upon locale, area, type of Depends upon locale, area, type of

crime and conditionscrime and conditions

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Crime Scene Searches Crime Scene Searches

Typical Typical search search patternspatterns

Outer to Outer to innerinner

Saferstein “Criminalistics”

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Collecting EvidenceCollecting Evidence

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Blood Spatter Analysis

Cast’s of Physical Evidence

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What determines the type and manner of What determines the type and manner of collecting and preserving physical evidence?collecting and preserving physical evidence?

The nature of the The nature of the evidenceevidence

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Q. What type of evidence is to be Q. What type of evidence is to be retrieved from a deceased victim for retrieved from a deceased victim for examination in the crime laboratory?examination in the crime laboratory?

ClothingClothing Fingernail scrapingsFingernail scrapings Head and pubic hairsHead and pubic hairs ““Orifice” swabsOrifice” swabs BulletsBullets Hand swabs for gunshot residuesHand swabs for gunshot residues

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Packaging EvidencePackaging Evidence

Prevents any change after collectionPrevents any change after collection Proper identificationProper identification Prevents cross contamination Prevents cross contamination

(separate packaging)(separate packaging) Preserved intact (e.g., blood on Preserved intact (e.g., blood on

clothes)clothes) Crime scene safetyCrime scene safety

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Q. Who is Q. Who is responsible for the responsible for the

integrity of integrity of handling the handling the evidence?evidence?

Chain of Custody: is a Chain of Custody: is a list of list of all personsall persons who who came in possession of came in possession of an item of evidence.an item of evidence.

Initials and date Initials and date should be recordedshould be recorded

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Chapter 2Chapter 2

Physical EvidencePhysical Evidence Legal PrecedentLegal Precedent Evidence TeamEvidence Team Crime Scene SearchesCrime Scene Searches Evidence Collection and PackagingEvidence Collection and Packaging Chain of CustodyChain of Custody