Kathy Blair is found stabbed to death in her bedroom in Texas; the gruesome crime scene puzzles investigators until an unlikely clue that is captured in the darkness puts them on the trail of a depraved killer.

The murder of a college student in Vincennes, Ind., may go unsolved until a second crime puts detectives on the heels of a serial killer, and police turn to the killer's shocking pattern of violence for clues.

After the battered body of a young woman is found dumped at a landfill in Lubbock, Texas, detectives race to collect evidence hidden in acres of trash.

Investigators in Prince George's County, Md., are chasing the shadow of a brutal killer who is targeting mothers and daughters; their investigation brings them face to face with a predator.

When a free-spirited young woman is found murdered in her kitchen, police in Chicopee, Mass., have no shortage of suspects; detectives realize the clue that leads to her killer is actually hidden in plain sight.

When a single mother's car is found abandoned on a lone stretch of highway in Illinois, detectives are forced to turn to forensic evidence to piece together the secrets of her disappearance.