Forensic Files: Episode - "Guarded Secrets" on truTV.com

Forensic Files: No witness. No leads. No problem. All New, 10pm Monday

"Smoking Out a Killer"
The murder of a young college student leaves a town in shock. Coincidences in the case leave police wondering if it is the work of a serial killer. But a lack of evidence leaves this 1981 case cold. But 25 years later, with the advancement of DNA technology, police are dealt a surprising twist and are able to catch the killer with the help of a cigarette. TV-PG V

The following forensic terms are used in this episode. For fuller definitions, click on any term.

• Autopsy - The internal examination of a body after death; performed to confirm or determine the cause of death.
• DNA - Deoxyribonucleic Acid. Constructed of a double helix, DNA is the genetic material contained in cells.
• DNA Profiling - The process of testing to identify DNA patterns or types.
• DNA Databanks - Databases which store DNA profiles collected from various classes of offenders.
• Evidence - Anything that has been used, left, removed, altered, or contaminated during the commission of a crime.
• Fingerprint - The unique patterns created by skin ridges found on the palm sides of fingers and thumbs.
• Medical Examiner - A medical doctor who determines causes of death, performs autopsies, and acts as an expert witness in criminal and civil trials where cause and/or manner of death are relevant.
• Polymerase Chain Reaction (PCR) - Scientists often refer to PCR as "photocopying DNA," since it allows them to rapidly replicate DNA molecules. The technique usually is employed when a given sample of DNA is too small for forensic testing.
• Trace Evidence - Material deposited at a crime scene that can only be detected through a deliberate processing procedure.