Mr. Cruel is the alias attributed to an unidentified Australian serial child rapist who perpetrated attacks on three girls in the northern and eastern suburbs of Melbourne, Victoria, during the late 1980s and early 1990s. He is also the primary suspect in the 1991 abduction and murder of a fourth victim, Karmein Chan. The name Mr. Cruel originated from a headline in the Melbourne newspaper, The Sun.

To date, Mr. Cruel has not been apprehended, and the three confirmed assaults, along with the suspected murder, remain unresolved cold cases. A reward of A$200,000 has b00.

Authorities characterize Mr. Cruel as exceptionally intelligent. He meticulously orchestrated each attack, conducted thorough surveillance of the victims and their families, ensured the absence of forensic evidence, concealed his identity by always covering his face, and employed red herrings to mislead family members and law enforcement. He exhibited a calm demeanor, taking his time during the assaults; in one instance, he paused in a victim's home to consume a meal. He threatened to harm his victims or their family members using a knife or handgun.