The New Detectives

For homicide investigators, it's a race against time when they track their deadliest foe: a serial killer who murders to feel alive.

When a killer turns a gun on a victim, ballistic analysis is key to cracking the case. Each shot fired leaves behind its own clues, allowing scientists to target murderers with deadly aim.

When theft is committed, something valuable is stolen. But when a criminal needs a new identity, theft becomes lethal.

The role of witnesses in the crime.

Murder victims are often lured to their death by someone they trust, someone with "Deadly Intentions." Examples: a responder to a newspaper ad in Virginia; a "girl" that a Texas Aggie student met in an Internet chat room; and a California family member with an ulterior motive.

Examines the double murder of Jose Trias and Julie Gilbert* and the murders of Carrie Love by Jesse Pratt in Klamath Falls, Oregon and Susan Bauer*. *Victims' pseudonyms.

Investigators rely on forensic odontology - the examination of dental evidence - to identify a body from a single tooth and to catch two ruthless killers from their bite marks.

Examining crimes committed by military personnel, including the case of a Marine Corps sergeant who reported his wife missing and found himself charged with murder; and a sailor killed with his own gun.

Some homicide cases go unsolved for years. It takes diligence and cutting-edge technology to catch suspects who believe their crimes have been forgotten.

The elements of nature can reduce a body to bones in a matter of weeks. Combining art and science, forensic anthropologists can give victims a face long after they've been forgotten.

Forensic scientists find clues written in blood as they investigate the murders of three women who were killed by men who once loved them.

Three men wrongly convicted of crimes are ultimately set free by DNA analysis.

Forensic artists turn witness statements into pictures to recreate the faces of killers.

For the forensic entomologist, insects that nest in corpses are like witnesses to the crime. By studying their behavior, scientists learn everything -- from when a murder was committed to what sort of weapon was used.

A millionaire is murdered for a stash of buried treasure. A young woman dates violent men, only to be killed by her best friend. A decomposed body is found but the victim's organs look as if he had died the day before. When real crimes are stranger than fiction, forensic science can sort fact from fantasy.

Photography has long been a fundamental tool in homicide investigations. A single image can hold enough information to identify a suspect and preserve vital clues long after a witness's memory fades.

Investigators dispute the innocence of teens involved in murders.

Two heads are better than one. When killers are cunning and truth elusive, a private think-tank called the Vidocq Society can provide investigators with fresh perspectives on cold cases.