A gruesome attack on an elderly couple leaves Phoenix police baffled. But a string of similar unsolved cases could lead detectives to the vicious perpetrator.

In Pennsylvania, the body of a computer programmer is found submerged in a bathtub. Leads are scarce until detectives uncover a series of troubling voicemails.

When a couple are killed in their bedroom in a quiet Maryland town, Det. Joe Bellino wonders if the answer lies with their daughter, who bore witness to both murders.

The body of a North Carolina teen is found in an empty dirt lot. Det. Josh Hamilton traces a series of strange transactions to expose an ugly truth.

In Chincoteague, Virginia a young mother fails to return to the pizza shop where she works after being sent on a delivery.

A med student is found pinned to her bedroom floor with a large knife. Det. Frank Dillard must employ his skills as an interrogator to hunt down a serial killer.

Some three miles off the Jersey shore, boaters discover the remains of a 16-year-old girl. An unlikely clue leads detectives to the killer's cold-blooded conspiracy.

When a young realtor plunges to his death from the 14th story of a Miami high-rise, first responders assume suicide. But Det. Joe Shillaci suspects foul play.

A young woman is brutally murdered just steps away from an infamous homeless encampment. Detectives hunt for a depraved serial killer.

The abduction and murder of a young schoolteacher shocks a New England town. Veteran investigator Robert Cushing is appalled by the depravity of the killer's plan.