Fingerprints
Solving a crime means looking for any detail to find out whodunit and a useful way to identify an individual is through their fingerprints left at a crime scene. Fingerprints are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs. Each person has his or her own specific fingerprint. No two people share the same fingerprint, which make them such an important forensic tool. DNA fingerprinting gives the criminalist an accurate tool for using the tiniest specs of genetic material to identify any individual who could have been present at the crime scene. (Lyle) There are three types of fingerprint impressions that may be found at a crime scene. The three impressions are latent, patent and plastic. Each has a differing role in fingerprint identification. In latent impressions, the skin has deposits of oil and perspiration that normally coat the surface. Patent impressions are the result of transferring foreign substances that leave a fresh coating on the skin. (Byrd) Examples consist of paint, tar, grease, blood, or ink. Plastic impressions are deposited when the hands, fingers, or feet are pressed into a rubbery material, which retains the ridge detail. (Byrd) Examples are clay, wet paint, blood, or tar. Fingerprints can be detected using different methods that rely on the type of print and its surface. Methods vary and use tools involving powders and various chemicals, which include iodine and Ninhydrin spray.
Bibliography
Byrd, Mike. Ridge Detail at a Crime Scene. Retrieved July 5, 2014, from
http://www.crime-scene-investigator.net/prints.html
Lyle, D.P. MD. (2004). Forensics for Dummies. NJ: Wiley Publishing, Inc.