After a nationwide search, the mutilated bodies of seven backpackers were recovered in the Australian outback. What drove the murderous rampage of Ivan Milat? 5/6 (S)

A loner and a misfit, Dennis Rader was not a stereotypical serial killer. He called himself BTK in honour of his murder method: bind, torture, kill. A profile of Dennis Lynn Rader, one of the major criminals of the 20th century.

They're perhaps the most notorious killers in British history - Fred and Rose West, an unassuming couple from Gloucester, in the west of England. From the 1970s to the early 1990s Fred and Rose murdered twelve people - including some of their own children - before burying their bodies in the cellar and under the patio of the family home.

While in jail, Johann Unterweger's writing made him a celebrity. Hailed as a model for rehab, he was granted parole but soon went back to strangling prostitutes.

In March 1999, Sipho Twala was convicted of the murder of sixteen women, three rapes and one attempted murder and is currently serving 506 years in prison.

Killing as many as five women a month, church-going Gary Leon Ridgeway pleaded guilty to the murders of 48 women in November 2003, earning him the most murder convictions in the US.