Season 4

When a young woman turns up dead in South Texas, Captain Calderon fears the killer has disappeared into Mexico. As more bodies turn up, investigators pick up on the trail of a serial killer, leading to a showdown in the streets of Laredo.

In Minnesota, firemen put out a housefire and find a woman's body inside; Agent Rob Fraik learns that the victim was babysitting a friend's daughter, who is now missing; it is a race against time to track down the killer with a horrifying motive.

Police find an accomplished U.S. Forest Service worker executed beneath a mound of snow in Northern California; a missing wallet and a pair of jumper cables send Investigator Greg Hagwood on a multi-state manhunt for the killer.

Deep in the kudzu of Alabama, police get a call about the body of a young man burned beyond recognition; Detective Kevin Palmer turns to the victim's phone records and picks up on a plot to lure the victim.

The body of a South Carolina man turns up floating in the Black River. Investigator Allen Morris, working his first homicide case, must scrutinize the victim's wife and mistress and ultimately untangle the web of deceit surrounding his disappearance.

Amongst the ashes of a barn fire, N.C. investigators discover the remains of two dismembered women; agent Nick Deming must dig into the victims' personal lives to uncover a revenge scheme and a killer.

A mother raises the alarm when her daughter goes missing from the Ault, CO house she had recently moved into. While Det. Ben Endreson is investigating, an unusual suspect comes forward to confess her involvement, but her story doesn't quite add up.

In the Miami suburbs, a hard working mother from Trinidad vanishes into thin air; detectives Danny Smith and Jonathan Zeller soon uncover her secrets but then are stalled until they come up with a highly unusual way to smoke out the perpetrator.

A scene straight out of a horror film unfolds outside of a Colorado police station, leaving one woman clinging to life and a second violently abducted; Det. Rick Archer soon uncovers a disturbing pattern that may have started a decade earlier.

Investigators uncover a tangled web of relationships and bizarre fantasies after discovering a hardworking father's lifeless body.