
An in-depth look at some of the world's most dangerous murderers.

A profile of Richard Roszkowski, the Connecticut triple-murderer who killed his ex-girlfriend, her nine-year-old daughter and another man in a brutal attack in 2006.

Scottish serial killer Robert Black attacked four young girls between 1981 and 1986; he was sentenced to life imprisonment at HMP Maghaberry with a minimum sentence of 35 years and was linked to 13 other child murders.

Keith Jesperson, known as the Happy Face Killer, brutally killed at least eight women across five American states in the early 1990s.

Christopher Halliwell's found guilty of murdering two women.