The Hillside Stranglers, tortured and murdered women before dumping their bodies around the Los Angeles hillsides. No one was off limits to Richard Ramirez, the Night Stalker's, rapes, assaults and murders around California. Paranoid schizophrenic Peter Sutcliffe, the Yorkshire Ripper, committed sexual homicide against women in the north of England.

Chester Turner, according to LAPD, is the most prolific serial killer in the history of Los Angeles. Joanna Dennehy became only the third woman in UK history to be jailed forever without parole for her brutal murders of three men. In Sydney, the most vulnerable of residents were at risk from the "Granny Killer".

Fostering an image as a kindly medical professional, Dr Shipman had for years cunningly disguised his addiction to drugs and killing his patients. Dorothea Puente appeared to be a mild care home manager. So when police detective John Cabrera knocked on her door it was for information and not the haul of bodies he would eventually find.