A behind-the-scenes look at major crime investigations through the eyes of the FBI crime lab. Until recently, it has been the world's least accessible crime lab but viewers are now able to witness the actual process of some of the FBI's most famous investigations, through dramatic re-enactments and interviews with agents and scientists. As the agents gather seemingly unremarkable clues, they transform them into hard evidence - the kind of evidence that brings a criminal to justice.

In June of 1979, a young woman finishes her shift at a convenience store in Ocean City, MD. As she leaves the store, a man identifying himself as a police officer flashes a badge and tells her she is a suspect in a series of robberies.

Before she knows it, she is handcuffed and pushed into the back seat of an unmarked car. After being driven to an abandoned building, she is raped and tortured for 28 hours. Her tormentor photographs the whole ordeal. The dazed and bloodied girl is dumped on the side of the road.

Two years later, a 19-year-old woman is pulled over in Manassas, VA by an undercover police car with flashing red lights. She too is abducted by the impersonator and subjected to a similar ordeal of rape and torture.

Although she survives, a Louisiana real estate agent is not as lucky. In April of 1982, Jean McPhaul shows a new home to a man calling himself "Dr. Zack". The next day, McPhaul's body is found hanging from a beam in the attic. She has been stabbed and strangled.

During the course of the investigation, eleven unsolved murders and countless rapes are attributed to the same unknown perpetrator. Although the crimes take place in seven different states, each of the cases are similar enough to make the FBI suspect they are looking for one man.

The fledgling FBI Behavioral Sciences Unit is brought in to create a profile of the kind of man capable of such horrible crimes. Years go by, producing only one certainty-as long as he is free, more women will die.

On May 25, 1983, Secret Service agents arrest a man passing counterfeit bills at a mall in Knoxville, Tennessee. Inside his car, they find thousands of dollars in fake currency, guns, pornography, a portable pharmacy of various illegal drugs, nine forged driver's licenses, 14 license plates and a mail-order police badge.

The owner of the car is James Mitchell DeBardeleben II, a 45-year-old career criminal. Inside DeBardeleben's garage, investigators find a large-format Icoflex camera (ideal for counterfeiting), a single aluminum printing plate for a 20-dollar bill, and over 52,000 dollars of counterfeit money in various stages of the manufacturing process.

They also find gun cases, ammunition, police paraphernalia, ski masks, drugs, blood-stained women's clothing, whips, a bag which investigators describe as a "death kit," and hundreds of brutally explicit photographs of women and girls.

Although DeBardeleben's face is never clearly shown in any of the photographs, FBI forensic photographer Peter Smerick maps the moles and freckles on DeBardeleben's arms and torso to show that they perfectly match the moles and freckles on the arms and torso of the perpetrator in the photographs. The killer's own photos put him in prison.

Investigators believe that DeBardeleben committed his first murder in 1965, 18 years before he was finally caught. He is indicted for 11 murders in 9 states, tried and convicted in six cases, and sentenced to serve 375 consecutive years in prison.