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Transcript of Trace Evidence
Who is Edmond Locard?
Edmond Locard was a pioneer in forensic science and was known as the Sherlock Holmes of France.
The Locard Exchange Principle
Locard came up with the basic principle of forensic science, stating that: "Every contact leaves a trace". This is known as the Locard Exchange Principle.
9 mm automatic
DAVID FARADAY (17) & BETTY LOU JENSEN (16)
TIME/DATE: 23:15 - 20 December 1968
CASE #: V-25564
LOCATION: Lake Herman Road, Vallejo, California
DARLENE FERRIN (22) & MIKE MAGEAU (19)
TIME/DATE: 23:55 - 4 July 1969
CASE #: 243146
LOCATION: Blue Rock Springs Park, Vallejo, California
CECELIA SHEPARD(22) & BRIAN HARTNELL(20)
TIME/DATE: 18:15 - 27 September 1969
CASE #: 105907
LOCATION: Lake Berryessa, Napa, California
PAUL STINE (29)
TIME/DATE: 21:55 - 11 October 1969
CASE #: 696314
LOCATION: Washington St., Presidio HeightS, San
CHERI JO BATES - 1966
face fully covered
Collection of Trace Evidence
What is Trace Evidence?
Trace Evidence is the connection between a victim and a suspect. It's what's left at the crime scene or exchanged in physical contact. Hair, blood, footprints, gunshot residue, soil, tool marks, fingerprints, paint chips, fibers and fabrics are all examples of trace evidence.
1) Scraping - use flat objects like a spatula to scrape items from flat surfaces; transferred to evidence bag or a container
2) Picking – Tools, such as forceps or needle-nose pliers are usually used to remove strands of hair from other objects
3) Vacuuming - Special vacuum cleaners (usually hand-held) collect several items at once-- vacuums have filter traps to catch the evidence
4) Lifting - sticky side of special tape to collect evidence
5) Combing – combs the hair of an individual to collect debris or foreign objects, such as hair or dandruff from suspect
6) Clipping – trimming of fingernails to get tissue and DNA of attacker-- If victim struggled with attacker, may have scratched killer
Trace Evidence Collection Kit
Crime investigation: physical evidence and the police laboratory.
Interscience Publishers, Inc.: New York, 1953
Trace Evidence Collection. (n.d.). Retrieved November 12, 2014, from http://www.leelofland.com/wordpress/trace-evidence-collection/
Crimes and Clues. (n.d.). Retrieved November 10, 2014, from http://crimeandclues.com/2013/04/05/trace-evidence-hair/
Ramsland, K. (n.d.). Trace Evidence. Retrieved November 11, 2014, from http://www.crimelibrary.com/criminal_mind/forensics/trace/5.html
Rankin, S. (2005, January 1). Trace Evidence. Retrieved November 15, 2014, from http://forensicsciencecentral.co.uk/traceevidence.shtml
About Trace Evidence & Real Case
Crime Scene Investigator
Crime Scene Investigator photographs, tags, recovers, and keeps track of all the evidence found at a scene-- investigate the crime
Scene of Crime Officer (SOCO)
Scene of crime officer collects all the evidence at the crime scene and analyze it later
Examiner analyzes the evidence brought back to the lab
Investigators found green beaded necklace with blood along with dead body of Elizabeth Marshall with two bullets through head. Investigators also collected saliva from the food, lipstick stains from cups, strands of hair, bullets, and skin found under Marshall's fingernails.
April 22, 2014, Elizabeth Marshall strangled and shot to death at Gliss restaurant downtown Sault Ste. Marie. Partner Emily Mosby was present at crime.
Importance of Trace Evidence
Forensic scientists use trace evidence to reconstruct crimes, and to describe people, places and things involved in them
Crime scenes almost always contain trace evidence, usually caused by the perpetrator not knowingly coming into contact with surfaces and leaving behind or picking up objects