More than twenty years after two women are similarly raped and strangled in North Philadelphia, DNA technology breakthroughs renew hope that the results could finally lead detectives to a brutal killer on the loose.

A skeleton is discovered on the edge of a high school football field, during a game of catch. It takes a forensic sculptor, tireless detective work, and some luck, to finally bring the mysterious killer to justice.

A young mother and her family's slaying provides detectives with a chilling link to another murder gone cold. Now, they must work fast to make an arrest before the killer strikes again.

When a bright, young, exotic dancer is found dead at the bottom of a 12-story bridge, detectives must determine if it's a suicide or the work of a sinister character who wanted more than a dance.

A wild party ends in terror as a young mother's cries for help fall on deaf ears. When detectives retrace her final steps they find a trap with no way out.

Elaine Goldberg's body is found in a lot in Philly's "Badlands," and police believe the woman is a prostitute who has overdosed, but when two more bodies turn up in the same part of town, detectives fear there may be a serial killer on the loose.

A woman goes missing, and detectives discover a secret relationship.

A missing teen spurs an intense search by his parents and detectives.

In 1979, bar manager Harriet Simmons disappears during a trip to Nashville.

A single mother is discovered murdered behind a church.

Robert Hansen hunted down women for sport in the Alaskan wilderness.

A man eliminates witnesses before blowing up the Alaskan Pipeline.

A missing couple is found murdered in the backwoods of Chulitna, Alaska.

A girl is lured into a mall by an unknown man and is never seen again.

Amy's killer remains at large as a cavalcade of suspects emerges.

Amy's killer remains on the loose, and the case goes nationwide.