Trace Evidence

Trace evidence on a shoe.

R.C.M.P.

© R.C.M.P.. All Rights Reserved.


Forensic science involves many different disciplines including alcohol, anthropology, chemistry, document identification and forgery, entomology, fingerprints, firearms, trace evidence, odontology, biology and pathology (to name a few). Professionals in these fields use the latest technology and research to assist the legal system to determine a suspect’s guilt or innocence.

A piece of evidence found at the scene of a crime will often be analyzed by several different methods to get the most information from it. For example, a shoe may be examined for bloodstains (studied by biology, DNA analysis), trace evidence (broken glass or similar type of dirt found on suspects shoe and crime scene), gunshot residue (may be on suspect’s clothes or hands as well) etc. A person or persons at the scene when a crime is committed will almost always leave something behind and take something away with them.
Forensic science involves many different disciplines including alcohol, anthropology, chemistry, document identification and forgery, entomology, fingerprints, firearms, trace evidence, odontology, biology and pathology (to name a few). Professionals in these fields use the latest technology and research to assist the legal system to determine a suspect’s guilt or innocence.

A piece of evidence found at the scene of a crime will often be analyzed by several different methods to get the most information from it. For example, a shoe may be examined for bloodstains (studied by biology, DNA analysis), trace evidence (broken glass or similar type of dirt found on suspects shoe and crime scene), gunshot residue (may be on suspect’s clothes or hands as well) etc. A person or persons at the scene when a crime is committed will almost always leave something behind and take something away with them.

© 1998 CHIN. All Rights Reserved.

Forensic scientists work together in order to solve a crime (just like the characters in the game). The shoe shown above may contain different materials that would be of interest to different forensic departments. Bloodstains may be sent to biology and toxicology, the firearms section may look for gunshot residue, the chemistry section may try to identify the soil samples and the trace evidence may contain hairs or fibres from the scene of the crime. Most of the work in the different departments of the forensic labs consist of finding out...

if a substance is present,  determining the substance’s concentration, where or whom the substance came from, if the substance was the cause of death or if it contributed to the death, matching of substances or materials providing expert testimony on these subjects in a court of law.
Forensic scientists work together in order to solve a crime (just like the characters in the game). The shoe shown above may contain different materials that would be of interest to different forensic departments. Bloodstains may be sent to biology and toxicology, the firearms section may look for gunshot residue, the chemistry section may try to identify the soil samples and the trace evidence may contain hairs or fibres from the scene of the crime. Most of the work in the different departments of the forensic labs consist of finding out...

  • if a substance is present,
  •  determining the substance’s concentration,
  • where or whom the substance came from,
  • if the substance was the cause of death or if it contributed to the death,
  • matching of substances or materials
  • providing expert testimony on these subjects in a court of law.

© CHIN. All Rights Reserved.

Typing classifies a sample (like blood or DNA) into a category. The more categories that a sample is in, the less likely it is to have come from more than one person. For example, let’s type a person’s physical characteristics. If a person has blue eyes, it could be almost anyone, but if he/she has blue eyes, "A (-)" blood, 188 cm tall, female, with a scar over the left eye, the number of people this could be is greatly narrowed. The tests for typing of blood, DNA typing or fingerprinting are much more powerful tools than the broad physical characteristics mentioned earlier. If a criminal left behind a blood or skin sample under the nails of the victim, DNA analysis can confirm the identity of this sample to the suspect.
Typing classifies a sample (like blood or DNA) into a category. The more categories that a sample is in, the less likely it is to have come from more than one person. For example, let’s type a person’s physical characteristics. If a person has blue eyes, it could be almost anyone, but if he/she has blue eyes, "A (-)" blood, 188 cm tall, female, with a scar over the left eye, the number of people this could be is greatly narrowed. The tests for typing of blood, DNA typing or fingerprinting are much more powerful tools than the broad physical characteristics mentioned earlier. If a criminal left behind a blood or skin sample under the nails of the victim, DNA analysis can confirm the identity of this sample to the suspect.

© CHIN. All Rights Reserved.

If you would like to learn more about forensic science, the Royal Canadian Mounted Police laboratories would be a good place to start. The R.C.M.P. forensic laboratory services consist of approximately 300 forensic scientists, technologists, and administrative personnel in six regional laboratories (Vancouver, Edmonton, Regina, Winnipeg, Ottawa and Halifax). The Forensic Laboratory Services Directorate is part of the R.C.M.P.’s National Police Services program and they supply services to all Canadian Police Agencies, the Canadian Courts and Government Agencies.

Visit their web-site at : http://www.rcmp-grc.gc.ca/html/labs.htm

Another important Laboratory, whose web-site can be consulted, is the Montreal Laboratoire de sciences judiciaires et de médicine légale. The first facility of its kind in North America, the Laboratory is a pioneer in the field of forensic medecine. In October 1996, the Laboratory acquired the status of independent service unit but remained attached to the Ministère de la Sécurité publique.

Visit their web-site at : http://www.msp.gouv.qc.ca/labo/index_en.asp
If you would like to learn more about forensic science, the Royal Canadian Mounted Police laboratories would be a good place to start. The R.C.M.P. forensic laboratory services consist of approximately 300 forensic scientists, technologists, and administrative personnel in six regional laboratories (Vancouver, Edmonton, Regina, Winnipeg, Ottawa and Halifax). The Forensic Laboratory Services Directorate is part of the R.C.M.P.’s National Police Services program and they supply services to all Canadian Police Agencies, the Canadian Courts and Government Agencies.

Visit their web-site at : http://www.rcmp-grc.gc.ca/html/labs.htm

Another important Laboratory, whose web-site can be consulted, is the Montreal Laboratoire de sciences judiciaires et de médicine légale. The first facility of its kind in North America, the Laboratory is a pioneer in the field of forensic medecine. In October 1996, the Laboratory acquired the status of independent service unit but remained attached to the Ministère de la Sécurité publique.

Visit their web-site at : http://www.msp.gouv.qc.ca/labo/index_en.asp

© CHIN. All Rights Reserved.

Learning Objectives

The learner will:
  • Develop enthusiasm and continuing interest in the study of science
  • Summarize the work of forensic scientists
  • Define forensic science

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