
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.

Police find 30-year-old Kayla Brown, who had been held hostage for 65 days by seemingly respectable estate agent Todd Kohlhepp, tied up and locked in a storage container.

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.