The Crime Scene A look into evidence gathering
- Slides: 66
The Crime Scene A look into evidence gathering and processing Mrs. Toth Some slides by Mrs. Ryan
Crime Scene Definition Crime Scene vs. Scene of the Crime Includes planning areas, flight paths, staging areas, surveillance Location of the actual crime
What is the Job Title? • In the United States, crime scene investigators are usually called “criminalists” • In the United Kingdom, crime scene investigators are usually called “scene of crime officers”
What is the Job Title? • Job titles in forensic fields vary widely from jurisdiction to jurisdiction • Example: A crime scene analyst is a civilian employed by the police department in Las Vegas - allowed to carry guns - depending on the department, analysts can be civilian or law enforcement
What is the Job Title? • In Albany, 8 detectives make up a “support unit” that collects all areas of evidence instead of individual units
Lockard’s Theory: Review • Dr. Edmund Locard’s theory for the exchange of evidence is widely recognized as the cornerstone of forensic science. • Locard’s theory: Whenever two objects come into contact, a transfer of material will occur. Evidence that is transferred can be used to associate objects, individuals or locations.
Lockard’s Theory: Review Through evidence, try to connect the: Victim Suspect Crime Scene
Every contact leaves a trace… Examples of trace evidence that is picked up or left behind: • Hair, Fibers - From the individual, their spouse, child, pets, victim, etc. • Soil, sand, plant matter, sawdust - Picked up on a person’s shoes
Class versus Individualized Evidence • Class evidence - evidence that can only be grouped into a general category; cannot be pinpointed to a direct person or object ex. Black Lab Hair • Individualized evidence - evidence that can be pinpointed to only one individual or object; unique ex. Fido’s hair (a black Labrador) through DNA
Class versus Individualized continued Trace Evidence Hair Dog Hair Class Black Labrador Retriever Hair DNA from hair individualized to Fido (a black Labrador Retriever) Individualized
Class versus Individualized continued • A single piece of class evidence can rarely convict someone, though it may exclude a suspect. • However sheer numbers of class evidence can make coincidence unlikely. Ex. Porco case
“Common Source” Not “Match” • When two objects share a class identity • For example, white tennis shoes – The “common source” can be the factory, owner, or even where found – Suspect owns white tennis shoes and one is left at crime scene; try to see if the CS shoe came from a “common source” as the one in his apartment • Example, fibers on a body in ditch – Fibers on body belong to an automobile – Find a suspect, try to see if fibers in his car are from “common source” as the fibers on the body
Evidence Types Evidence Direct Circumstantial Biological Physical
Evidence Types 1. Direct Evidence: evidence that, if true, proves an alleged fact, such as eye witness account of a crime Ex. Police dashboard video cameras Witness testimony
Evidence Types 2. Physical or Real evidence (A type of indirect evidence): A tangible object related to a crime. Ex. Bloody knife at crime scene 3. Testimonial evidence (A type of direct evidence): Verbal accounting of an incident by a witness, victim or suspect. Ex. Neighbor says they have seen Suspect A with a knife at their house
Evidence Types cont. 4. Indirect or circumstantial: evidence that supports other evidence; implies or infers facts; secondary Ex. Suspect A has expert training in knife skills; victim was stabbed to death in a technical manner
Value of Evidence • Physical evidence: Cannot lie, die, quit, forget …. etc. ; very good evidence!!! • Testimonial evidence: may change, be unreliable, be mistaken or source can become unavailable during the case; questionable and therefore not reliable!!
Physical Evidence Issues Often… • • • Not recognized, identified or overlooked Not legally collected Not properly collected and/or packaged Not properly stored Not properly tested Chain of custody issues
Maintaining a Chain of Custody • As evidence is collected, the evidence bag is initialed by the collector and dated • Anyone who possess the evidence during the investigation must sign for it as a record • Failure to document can have evidence excluded from case/trial
Evidence Issues continued • Most of the mistakes made in the collection, securing and testing of evidence can be attributed to the lack of training and understanding. Ex. OJ Simpson Case - mishandled evidence
Jon Benet Ramsey A Forensic Nightmare
John and Patsy Ramsey Jon Benet’s parents
The “War and Peace” of Ransom Notes
The Ramsey House
Jon Benet’s neck at autopsy
The garrote made from a broken paintbrush
The Autopsy Report
Jon Benet’s Grave
Why have protocols? • The errors made in the Jon Benet Ramsey case and in the Nicole Brown Simpson murder compromised the investigation • Proper procedure and methods would have prevented these errors
Processing the Crime Scene • Important to remember that crime labs DO NOT solve crimes • Only investigations by police solve crimes • Forensics merely helps the police to do their job
Processing the Crime Scene • 1 st Officer’s responsibilities – Preserve and protect the area; mark off larger than needed – Call for back-up – Log all who come in/out; controls evidence tampering – The enter/exit area of the perpetrator is recorded as well – Police must ensure suspect can not return to the scene to destroy evidence
Steps in Processing the Crime Scene 1. Provide medical assistance; save and preserve life
Steps in Processing the Crime Scene 2. Secure the scene • Arrest/detain suspects • Use crime scene tape, barricades, cars, officers • Exclude ALL unnecessary people • Initial walkthrough: -entry & exit? -overview of scene -any specialists needed? Saferstein video: Processing Keep a crimehands scenein pockets!
Steps in Processing the Crime Scene 3. Document the scene • Limited time available to work a crime scene » Three methods of crime-scene recording: 1. Photography 2. Sketches 3. Notes
Forensic Photographers • Important: Scene must be unaltered - if changed, photos could be inadmissible as evidence • Photos are taken of entire crime scene, including surrounding areas; enter and exit areas taken at various angles; adjacent rooms • Bodies are also heavily photographed in relation to where they are in the scene
Forensic Photographers • As physical evidence surfaces, they are photographed; often with something next to them to indicate size (ruler or measuring tape) • Photographers are only able to begin taking photos once they have been given the okay from the crime scene manager
Forensic Photographer • Equipment: – 35 mm and digital cameras; corresponding film – Standard light (flash) – Colored filters, light beams, UV (stains/fingerprints after treated with superglue or DFO), violet (gunshot residue/blood), blue and green light (prints/fibers/urine/semen)
Forensic Photographer • Key point about photography is that it allows the police to reopen a crime scene quickly, like a busy street - all evidence has been captured on film • They must be ready 24/7 • Extremely difficult job because reliant on this person’s experience to get all data
Sketches • After the photographer is finished, crime scene investigators make a rough sketch of scene • Shows the location of all objects • Objects are located from two fixed points in the room like walls or a doorknob; called DATUM • All measurements are made with a tape measure
N 3 ft 1 in 6 ft 3 in Measure from two fixed points
Sketches • Often use number or letter cards by evidence • Finished or final sketch is completed back at the lab using computers and drafting materials – Looks “finished” – Has a legend instead of labels
Notes • Notes are continuously gathered at a crime scene • Must identify the time evidence was found, location, description, who and how item was packaged • Notes can also be taken using a tape recorder and by video; later must all be written down
Steps to Processing the Crime Scene 4. Identify and interview witnesses - keep witnesses separated - don’t want stories contaminated
Steps to Processing the Crime Scene 5. Search the scene • Be thorough and systematic by following a search pattern. ex. line, grid, spiral, quadrant (which one is chosen depends on locale & size of area and # of officers) • Look for details… remember to look up too ! Read list of details to look for…
Systematic Search for Evidence • A thorough, systematic search of the crime scene necessary for court • Not necessarily done by forensic scientists • There are four general search patterns 1) Spiral search 2) Grid method 3) Strip or line method 4) Quadrant or zone search
Systematic Search for Evidence Spiral Grid Line/Strip Quadrant/ Zone
Systematic Search for Evidence Line Grid Quadrant Spiral
Steps to Processing the Crime Scene 6. Collect and package evidence • Wear gloves, booties, mask, “bunny suit” while collecting Note: After 30 min. you can leave fingerprints behind through gloves !
Collect and package evidence • Label each item as follows: What is it ? eg. Blue fiber Where found ? Who collected it ?
Collect and package evidence • Package each item separately and in proper packaging: • Examples: - Hairs/ fibers: paper bindle or glassine envelope
Collect and package evidence Powders: plastic bags
Collect and package evidence Blood, semen stains: paper bags (prevents bacterial and fungal growth) *dry out first
Collect and package evidence Weapons, bullets, casings: cardboard boxes (prevents scratches)
Collect and package evidence Arson evidence: air tight, lined metal containers (prevents corrosion and evaporation of accelerants)
Collect and package evidence Paper documents: envelopes (paper or Tyvek)
Collect and package evidence Glass evidence: plastic vials (prevents scratches)
Collect and package evidence • A hand-held vacuum with a special filter can be used to collect trace evidence • Crime scene evidence is extended into the autopsy room: – victim’s clothing; fingernail scrapings; head and pubic hairs; blood; vaginal, anal and oral swabs; recovered bullets from the body; hand swabs from shooting victims
Evidence Collection Kit
Steps to Processing the Crime Scene 7. Maintain Chain of Custody • Documentation of the movement of evidence from collection until case conclusion. • Crucial to maintaining integrity of evidence.
The Top Ten Ways to Botch an Investigation Go to the list
- Look up and down gif
- _____ is done with the first responding officer.
- Locard exchange principle
- Assessment is a process of gathering evidence of
- Stomata
- West memphis three crime scene photos
- Seven s of crime scene
- Types of crime scene
- Margaret schlosser autopsy
- Cameron todd willingham house address
- Compass point method
- Baseline measurement crime scene
- Crime scene factoring and quadratic functions answer key
- Why are crime scene sketches important
- Lake havasau az
- Intermediate crime scene search #2106
- Tcole intermediate crime scene
- Crime scene factoring and quadratic functions answer key
- Crime scene vocabulary
- Forensic science begins
- Crime scene sketch examples
- Crime scene photography management
- While the csi team is searching the crime scene, _____.
- Crime scene vocabulary
- Cretaceous crime scene
- Crime scene drawings
- The term encompasses all objects
- A crime scene sketch should include
- What is a grid search police
- Crime scene storyboard
- Robert pickton trailer
- Crime scene
- 2106 crime scene investigation
- Corpus delicti
- Crime scene reconstruction definition
- Crime scene investigation background
- Crime clip
- Crime scene inference
- Scsi unit fbi
- Crime scene
- Crime scene notes
- Grid linear spiral and quadrant are all
- Crime scene reconstruction involves forming a hypothesis
- Line/strip search pattern
- Crime scene photography log
- Youtube.com
- Csi search patterns
- Csi boston massacre
- Seven s of crime scene
- Subdatum point definition
- Phil spector crime scene
- Crime scene
- Sketch all serious crime and crash scenes:
- Intermediate crime scene investigation texas
- Cross-projection sketch
- Crime scene note taking
- Corpus delicti
- Class vs individual evidence
- John yelenic dentist
- Secondary sources
- Primary evidence vs secondary evidence
- Primary evidence vs secondary evidence
- Primary evidence vs secondary evidence
- Primary evidence vs secondary evidence
- Fiber evidence can have probative value
- Class vs individual evidence
- Explain how class evidence may be useful.