
Examining some of the most dangerous and prolific murderers in the UK and worldwide.
Teen Mhairi is killed on her walk home after a festive night; investigators trace her last steps, using CCTV and forensics that point to Gavin, a violent repeat offender whose history reveals how dangerous he truly is.
Andrew Dawson was given a second life sentence for the unprovoked murders of his two neighbors.
A profile of the killer who, after killing 22-year-old Julie Hogg, became the first person to be convicted under revised UK double-jeopardy laws.
A profile of the double-murderer who killed a 77-year-old teacher and a 59-year-old reverend.