ITV

The broadcaster meets Mark Riebe, who was convicted for one murder but has confessed multiple times to the abduction and killing of 13 women along Florida's Gulf Coast.

Although Riebe has since withdrawn his confessions, police believe he is one of the worst serial killers in Florida's history.

Piers uses Riebe's video and audio confessions, news archive and testimony to explore what sort of man would commit murder and then taunt the victims' families for nearly 20 years.