Blood In The Water: In 1980, a teenage girl was brutally murdered in her Colorado home. But in her last moments, she managed to leave investigators a clue to her attacker. (S6, ep 9)

Sin City Slaying: When 52-year-old Martha Doney was found dead in her Las Vegas home, police struggled for many years before bringing the case to a surprising conclusion. (S5, ep 9)

Triple Threat: When a California mother-of-two is found strangled in her home, detectives question whether she was the latest victim of a fledgling serial killer. (S4, ep 9)

Elemental Murder: State-wide panic ensues when a waitress is poisoned in Florida. One of the strangest sting operations in the state's history turns up an unlikely killer. (S3, ep 9)

Silent Night: When a young woman is found murdered in her Oregon apartment on Christmas Day, investigators soon learn the terrifying truth about her killer. (S8, ep 8)

Absent Teacher: In 1993, a primary school teacher went missing after her first day at a new job. Over the next two months, investigators pieced together the sinister puzzle. (S7, ep 8)

Brute Force: In 1987, Kentucky police discovered the body of 20-year-old Corinna Mullen in the boot of her car. But it would be many years before the case could be solved. (S6, ep 8)

Manufacturing Murder: In December of 1997, the bodies of three men and a woman were discovered in a Florida manufacturing plant. Who killed them and why? (S5, ep 8)

Murder On The Menu: Detectives grill a host of suspects when they discover the dumped and dismembered body of a chef. Can forensics confirm his unlikely killer? (S4, ep 8)

Death Of An Angel: In 1992, 17-year-old Angel Ormston failed to return from a trip to the shops. Had she run away? Five months later, her family discovered the awful truth. (S3, ep 8)