You have watched it on the TV show CSI, and noted how CSI technicians collect evidence from a crime scene in order determine the who, what, when, where, why, and how involved in a crime.
In a science called physical forensic science, there are four aspects involved. In this article, I will define the four aspects of physical forensic science so that the next time you watch CSI, you will have a better understanding of what police scientists talk about.
What is physical forensic science?
Searching for trace evidence, identifying the type of firearm used by studying its projectile, studying the handwriting of a signature on a document, and analyzing the ridges of fingerprints under a microscope all are a part of the physical aspect of forensic science.
Trace evidence refers to any small item of evidence such as glass, paint, fiber, hair, or soil. Such evidence puts the suspect at the crime scene or in direct contact with the victim. Matching glass shards found on the victim of a hit-and-run vehicle accident to glass shards taken from the broken turn signal lamp of the suspect’s car is a good example.
All you CSI: Miami fans know that this is right up Caleigh Duquesne’s alley. Firearms identification involves the examination of firearms and the bullets they fire, including ammunition, shell casings, shotgun shells, and fired bullets. Police scientists use microscopes or varying types of chemical analysis to identify the type of gun used to commit a crime and match any bullets fired from that weapon or shell casings to a weapon of interest.
Whenever an important document whose handwriting or authenticity is in question, a document analyst uses handwriting analysis to compare handwriting samples to questionable documents or signatures. Document analysis also may involve analyzing the chemical and physical properties of papers and inks or exposing indented writing–the indentations made on the page underneath one that was written on. In addition, document analysis also includes typewritten and photocopied documents that may have been altered.
Fingerprint analysts compare prints found at a crime scene to the fingers, palms, or soles of potential suspects. A print found at a crime scene can be compared with another print stored in a database such as the FBI’s Automated Fingerprint Identification System (AFIS) or from a suspect, victim, or bystander.
Hopefully, all four of these aspects of physical forensic science will give you a clearer picture of what is involved. All law enforcement crime labs use these methods to help bring a crook to justice.
For those of you who are science buffs, this article is food for thought.