In the US, a man and his accomplice go on a killing spree, leaving four dead in their wake. The police desperately search for the pair to put an end to their reign of terror. In the UK, a young student is found stabbed to death in his college room.

In Florida, USA, a woman goes missing with a large sum of money. Assuming foul play, the police are running out of time to find her, until someone is caught lying on camera. In the UK, the shocking murder of a woman in her own home sparks outrage.

In the US, a man desperately calls the police for help after he is attacked. Police work to crack the case using security footage and phone tracking. In the UK, a dog lover is found murdered in her rural home.

A businesswoman is in a whirlwind romance, but her newfound joy is cut short when her family finds her murdered. A bizarre confession reveals a deluded mind behind her death. In Northampton, England, a man with multiple stab wounds is discovered.

In the UK, a young woman fails to come home after a mysterious date. Her worried family desperately searches for her, only to discover a devious attempt at a cover-up. In the US, a young mother is found dead in a house fire.

In the US, a mysterious man buying yogurt is linked to a missing woman. His arrest leads to the discovery of four other women who have disappeared. Meanwhile, a young student gets into a taxi after a night out and never makes it home.

In Colorado, a dead woman in an abandoned car covered in trash is linked to two brothers who immediately become prime suspects. In Michigan, two black bags full of body parts are found in a shed after a young couple goes missing.

In Florida, a 13-year-old girl is found stabbed over a hundred times. A teenager with a knife obsession comes under suspicion. In Colorado, a woman picked up in a "creepy white van" after a night out is missing.

A horse-loving woman is stalked digitally and in person, but her cry for help is ignored, with lethal consequences. An estranged husband threatens to kill his wife after she helps him out of jail.

In Texas, a husband "fails" to stop his wife from taking her own life with a gunshot to the back of her head. Home surveillance reveals the truth. In Washington state, a man builds a bunker in secret with a diabolical plan for his wife and daughter.

A young UK student is raped and murdered. Surveillance footage traps a serial sex offender. A jazz musician and his new girlfriend are murdered a week apart by her jealous ex.

Pregnant Summer Tatum was shot twice in the head by her husband after she discovered his online affair. Andreen McDonald, a businesswoman, was killed by her husband, Andre, with a hammer.

Two cases of domestic abuse: Patricia Birmingham in the US and Marta Chmielecka in the UK, both killed by their partners, reveal the deadly consequences of toxic relationships.

Kira Steger's murder by her husband and Whitney Gray's fatal road rage shooting reveal the devastating toll of violence both in relationships and on the open road.