The Devil You Know

The disappearance of a Manhattan student is investigated in the Season 4 premiere.

A father of three is suspected of committing a series of attacks in Ocala, Fla.

The hunt for a serial killer in the Midwest is chronicled.

A sister suspects her troubled brother knows more than he should about women who are missing from the streets of Edmonton. She makes a shocking discovery when she looks inside his hockey bag.

A devoted son supports his dad through cancer treatment, only to find his world turning upside down as the truth emerges about his dad's double life.

A man goes missing after marrying an attractive blonde.

A motel owner looking for an online relationship becomes involved with a doctor who has secrets to hide.

A woman wonders if her lover is the man responsible for three Philadelphia killings.