His criminal history stretched across decades, beginning with a conviction for rape and murder while serving in the military — a sentence he ultimately escaped before reoffending. What makes Carignan a recurring subject in forensic and criminal history literature is less the final tally of confirmed victims than the pattern: a long institutional record that failed, at multiple points, to interrupt his capacity for violence.

Bradford's case carries an unsettling dimension beyond his two confirmed murders: the discovery of photographs depicting 54 unidentified women, released by the Los Angeles County Sheriff's Department in 2006, raised the possibility that his victims numbered far higher than the record reflects. He used the pretense of photography to gain access to women, a methodical approach that investigators believe may have concealed a much longer history of violence. The full scope of his crimes has never been established.

Operating in Yekaterinburg during the late 2000s, Khabarov became known for a distinctly methodical form of killing that earned him his alias — the use of electrocution as a murder weapon. Convicted in connection with at least two deaths but suspected in seven, his case attracted lasting scrutiny less for the crimes themselves than for what followed: a verdict of insanity, a psychiatric internment of only twelve years, and persistent allegations that his release was secured through bribery enabled by his family's wealth.

Brady and his accomplice Myra Hindley carried out a series of child murders in northern England across two and a half years, crimes that became known as the Moors murders and permanently altered public understanding of how such offenses could be committed in partnership. The victims ranged in age from ten to seventeen, and the cases left lasting scars — not least because the location of Keith Bennett's remains was never conclusively established despite Brady's later involvement in search efforts. Brady died in 2017 still subject to a whole life order, having never fully cooperated with authorities in a way that brought closure to all the families concerned.