The Crime Scene

1. The Crime Scene

2. Locard’s Exchange Principle Every contact leaves a trace! Whenever two objects come together they must affect each other in some way. Something is likely to be exchanged between them! Physical Evidence - anything that establishes a link between a crime and a person

3. Principle of Individuality Two objects may be indistinguishable, but no two objects are ever identical. Things can be put into classes or even individualized in useful ways.

4. Search and Seizure • Evidence at a Crime Scene • 4th Ammendment to the Constitution “The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

5. Search and Seizure • Evidence at a Crime Scene • 4th Ammendment to the Constitution “The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

6. Search and Seizure • 4th Ammendment to the Constitution • Allowances for Warrantless searches: • the existence of an emergency. • The need to prevent the immediate destruction of evidence. • A search made by consent of the person involved.

7. Collection of Evidence - Legal Precedent MINCEY v. ARIZONA (U.S. Supreme Court, 1978) • Drug bust that went wrong and an undercover police officer was killed. • Police spent 4 days searching and seizing evidence • Mincey arrested and convicted. • Supreme Court ruled evidence collected was inadmissible because it was not from a proper search and seizure. Evidence taken without proper authority is probably not legally admissible.

8. Collection of Evidence - Legal Precedent Michigan v. Tyler (U.S. Supreme Court, 1978) • Building destroyed by fire was put out in early AM. • Building left unsecured until 8 AM when a preliminary search was done (for cause of fire). • Subsequent searches (at 4, 7, and 25 days) removed additional evidence. • Tyler convicted of arson. • Supreme Court: • “…entry to fight a fire requires no warrant, and that once in the building, officials may remain there for a reasonable time to investigate the cause of the blaze. Thereafter, additional entries to investigate the cause of the fire must be made pursuant to the warrant procedures”

9. Physical Evidence • Must be recognized at crime scene. • What relates to the crime and what doesn’t. • Must be properly collected, preserved and controlled - from massive to microscopic • Only aids in investigations (evidence doesn’t solve crimes by itself) www.crime-scene-investigator.net

10. Evidence • TV shows misrepresent the rigor that occurs in finding the RELEVANT evidence • Reality: takes work, skill, time, experience, and insight • Must observe important pieces of info among background “noise” of the location

11. More Probative, Less Prejudicial • Evidence should be able to PROBE the question at hand, to provide unbiased information

12. Types of Evidence • Relevant Evidence: • Any evidence that will make the existence of any fact that is important to a case more probable or less probably • Probative Evidence: • Evidence that has the ability to prove or demonstrate something relative to the case • Prejudicial Evidence: • Evidence that must not be unfairly prejudicial to be allowed in court

13. Steps Taken at a Crime Scene • Secure and Isolate the scene. • Render medical help and arrest suspects (if needed) • Preserve and protect evidence (isolate area) • Exclude unauthorized personnel • Designate Officer in Charge (with authority) • Establish boundaries • Document site • Collection of Evidence

14. Evidence Team • Personnel Duties and Responsibilities • Team Leader • Photographer and Photographic Log Recorder • Sketch Preparer • Evidence Recorder/Evidence Recovery Personnel • Specialists

15. Evidence Team • Personnel Duties and Responsibilities • Team Leader • Assume control and access • Determine search pattern and assignments • Coordinate with groups involved • Continuously evaluate work • Release crime scene

16. Evidence Team • Personnel Duties and Responsibilities • Photographer and Photographic Log Recorder • Photograph entire scene (before and after entered) • Photograph victim, crowd, vehicles • Photograph evidence before it’s moved (including fingerprints, casts, etc.) • Photograph evidence both in wide view (position at scene) and close-up (with scale) • Possible use of video recording (does not replace still photography • Prepare photographic log

17. Capture Crime Scene

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

19. Details preserved

20. Evidence Team • Personnel Duties and Responsibilities • Sketch Preparer • Diagram area of scene (incl. orientation) • Rough sketch - accurate dimensions, orientation and location of evidence (from a fixed point) • Finished sketch - aesthetic appearance (usually done later sometime w/ CAD [computer aided drafting]) • Set forth major items of evidence on sketch (with scale) • Make measurements (double check)

21. Evidence Team • Personnel Duties and Responsibilities • Sketch Preparer Rough Sketch

22. Evidence Team • Personnel Duties and Responsibilities • Sketch Preparer Finished Sketches

23. Evidence Team • Personnel Duties and Responsibilities • Sketch Preparer

24. Evidence Team • Personnel Duties and Responsibilities • Evidence Recorder/Evidence Recovery Personnel • Have evidence photographed/sketched before collection • Describe evidence and location on container • Package evidence • Maintain chain of custody and evidence log • Ensure proper safety of collection (e.g., infectious materials)

25. Evidence Team • Personnel Duties and Responsibilities • Specialists • May include: • Anthropologist • Blood expert • Bomb technician • Criminalist • Engineer • Entomologist • Medical examiner • Odontologist • Surveyor • Etc.

26. Crime Scene Searches • Thorough and Systematic • Unbiased and not overlook any relevant evidence • Depends upon locale, area, type of crime and conditions

27. Crime Scene Searches • Typical search patterns • Outer to inner Saferstein “Criminalistics”

28. Collecting Evidence

29. Physical Evidence Blood Spatter Analysis

30. Identification Analysis Describe the components of a unknown sample in detail WHAT IS THE MATERIAL? Cocaine? Cotton fiber? Lead pipe? Where can we obtain this information?? 1. from a crime scene 2. From a weapon 3. From a suspects hands 4. From the victim during an autopsy Laboratory analysts carefully choose methods to properly identify a substance Multiple methods are used

31. Comparison Analysis Take unknown sample, and compare it with a known sample Determines is the two samples, unknown and “exemplar” have a common origin used with fingerprints, DNA, bullet fired, ecological samples Outcome help support if a suspect was at a particular time and place 2 types of Comparison Analysis - One to One matching - One to Many matching

32. How would you categorize these two lists of evidence (class or individual)? • Size 10 sneaker • Tire tracks of 2011 Mercedes • Blue eyes • A Caucasian male • Fingerprint from a glass bottle • Scratch pattern on .38 caliber shot gun • Blood stain • DNA sample from skin

33. 2 Categories of Characteristics Class Characteristics Individual Characteristics Relate the sample to a unique and specific origin with a high degree of certainty Pattern in a fingerprint Scratch on a test fired bullet • Those that place a piece of evidence in a broad group • Lead pipe • Model automobile tire • Types of blood (AB+) • BOTH FEATURES may be used to connect the crime to the criminal

34. What determines the type and manner of collecting and preserving physical evidence? • The nature of the evidence

35. Q. What type of evidence is to be retrieved from a deceased victim for examination in the crime laboratory? • Clothing • Fingernail scrapings • Head and pubic hairs • “Orifice” swabs • Bullets • Hand swabs for gunshot residues

36. Packaging Evidence • Prevents any change after collection • Proper identification • Prevents cross contamination (separate packaging) • Preserved intact (e.g., blood on clothes) • Crime scene safety

37. Goals of the Evidence Packaging • Prevent any changes in the item after collection • Prevent any possible cross contamination which other samples • Preserves the sample as intact as possible • Maintains safe environment • Ensures proper identification and chain of custody information for the item

38. Q. Who is responsible for the integrity of handling the evidence? • Chain of Custody: is a list of all persons who came in possession of an item of evidence. • Initials and date should be recorded • Where and when it was collected • How it was packaged and stored • A physical description of the item along with any identifying numbers

40. Chapter 2- general concepts • Physical Evidence • Legal Precedent • Evidence Team • Crime Scene Searches • Evidence Collection and Packaging • Chain of Custody