The founder of Aum Shinrikyo built a religious movement that blended apocalyptic prophecy with absolute personal authority, drawing in thousands of followers — including scientists and engineers whose expertise he redirected toward mass violence. The 1995 sarin attack on the Tokyo subway system remains one of the most significant acts of domestic terrorism in Japanese history, and the group's capacity for coordinated chemical warfare distinguished it from most other extremist organizations of its era.

Kopylov committed his series of killings and sexual assaults entirely within a single year, beginning when he was sixteen — a fact that positioned him among the youngest individuals categorized as serial killers in the post-Soviet Russian record. The crimes took place across Chelyabinsk Oblast between 2004 and 2005, and the age at which they were carried out became central to how authorities and the public understood the case.

A Dutch collaborator who turned on his own countrymen, Bruins spent the occupation hunting Resistance members for the German SD in the northeastern Netherlands, leaving behind victims whose fates — including the whereabouts of two murdered brothers — he took largely to his grave. The legal history is itself a document of postwar failure: a death sentence in absentia, decades of refuge behind German citizenship laws, a 1978 conviction that carried only a seven-year term, and a final case dropped in 2014 when the evidence had aged beyond recovery. He lived to ninety-four, outlasting nearly every avenue for accountability.

On a single day in December 1994, Salvi moved between two Brookline clinics and opened fire, killing two receptionists and wounding five others in attacks that became a landmark moment in the history of anti-abortion violence in the United States. The coordinated nature of the shootings — targeting staff rather than a single spontaneous act — distinguished the case and drew sustained national attention to the threat of extremist violence against reproductive health providers. He died in prison in 1996 while awaiting the outcome of his case.