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

Billy Dunlop killed Julie Hogg in 1989 but was acquitted after two failed trials.

The first woman executed by lethal injection after taking six lives.

Ali Qazimaj is an Albanian conman who brutally murdered an elderly couple in 2016.

Over a 25-year career of murder, Richard Biegenwald killed at least six people.