Mr. Cruel
"Mr Cruel" is an Australian paedophilic serial rapist who attacked three girls in the northern and eastern suburbs of Melbourne, Victoriain the late 1980s and early 1990s, and is the prime suspect in the abduction and murder of a fourth girl, Karmein Chan. A subsequent newspaper headline referred to the perpetrator as "Mr Cruel," a name adopted by the rest of the media.
Speculation
It has been theorised that Mr Cruel may have been the same person as the Golden State Killer, as surviving victims described a person similar if not exactly the same as the police sketches of the suspect. Child pornographer Robert Keith Knight was also named as the prime suspect in the disappearance of Siriyakorn Siriboon, one of Mr. Cruel's alleged victims.