Forensic Science and Identification Services
Forensic Science and Identification Services (FS&IS) is an integral part of National Police Services, with a mandate to provide quality investigative support services for front line policing. FS&IS provides a wide range of forensic programs and services to clients in Canada and internationally through:
*forensic science services,
* crime scene forensic identification,
* fingerprint identification and criminal record repositories and
* the National DNA Data Bank.
FS&IS programs and services form an essential part of virtually every criminal investigation - it assists investigators to solve crime. It strives to be leading edge in developing processes and methods to ensure that thelaw enforcement community receives quality and timely support in fighting crime.
Finger prints and DNA:
Sir Francis Galton was one of the first to indulge himself into the possibilities of using fingerprints as a form of identification. His work in this field inspired the creation of an early fingerprinting filing system, known as'icnofalagometrico', developed by an Argentinian police member, Vucetich, whom had had correspondence with Sir Francis. The first fingerprinting bureau was opened by Vucetich in 1892, the same year Sir Francis released his works on fingerprinting.
Even with the recent advancements made in the field of DNA analysis, the science of fingerprinting, dactylography, is still commonly used as a form of identification,whether it has been taken in the traditional way using ink and paper or scanned into a computer database. Fingerprint identification is based on the classification of fingerprint patterns, which can not only prove that a person was present at a crime scene, but can also be used to compare with the stored fingerprints of millions of other known criminals.http://library.thinkquest.org/04oct/00206/text_nts_fingerprinting.htm
Is DNA effective in identifying persons?
[answer provided by Daniel Drell of the U.S. DOE Human Genome Program]
DNA identification can be quite effective if used intelligently. Portions of the DNA sequence that vary the most among humans must be used; also, portions must be large enough to overcome the fact that human mating is not absolutely random.
Consider thescenario of a crime scene investigation . . .
Assume that type O blood is found at the crime scene. Type O occurs in about 45% of Americans. If investigators type only for ABO, finding that the "suspect" in a crime is type O really doesn't reveal very much.
If, in addition to being type O, the suspect is a blond, and blond hair is found at the crime scene, you now have two bits of evidence tosuggest who really did it. However, there are a lot of Type O blonds out there.
If you find that the crime scene has footprints from a pair of Nike Air Jordans (with a distinctive tread design) and the suspect, in addition to being type O and blond, is also wearing Air Jordans with the same tread design, you are much closer to linking the suspect with the crime scene.
In this way, by accumulatingbits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue that your suspect really is the right person.
With DNA, the same kind of thinking is used; you can look for matches (based on sequence or on numbers of small repeating units of DNA sequence) at many different locations on the person's genome; one or two(even three) aren't enough to be confident that the suspect is the right one, but thirteen sites are used. A match at all thirteen is rare enough that you (or a prosecutor or a jury) can be very confident ("beyond a reasonable doubt") that the right person is accused.
State crime lab analyst Kathryn Troyer was running tests on Arizona’s DNA database when she stumbled across two felons with...