His crimes unfolded on hiking trails in the Bay Area, where the isolation and the approach of unsuspecting victims gave him a tactical advantage he exploited repeatedly. All of the killings attributed to him occurred while he was on parole for prior rape and kidnapping convictions, making him a study in the failure of institutional safeguards. The detail noted by pathologists — that the act of tormenting victims caused his stutter to disappear — offers an unsettling window into the psychology behind the crimes.

Operating out of Pietermaritzburg over several years, Duma used his position as a taxi driver to access victims, a occupation that granted proximity and mobility that structured much of his offending. His crimes spanned theft, kidnapping, rape, torture, and murder — a range of conduct that resulted in eight life sentences across two separate convictions. Criminologists classified him as a disorganized killer, reflecting the variability in his methods and targets rather than a fixed, calculated pattern.

Beck's case stands out for the particular predatory logic at its center: she and her partner Raymond Fernandez systematically exploited the vulnerability of women seeking companionship through newspaper personal ads, turning loneliness itself into a mechanism of selection. The confirmed killings spanned two years and may have reached as many as twenty victims before their arrest in 1949. The case has retained public attention for decades, partly because of the emotional dimension Beck brought to the crimes — her jealousy of Fernandez's marks was itself a reported motive — and partly because of how ordinary the method of approach appeared to those who became targets.

Operating in postwar West Germany against a backdrop of social reconstruction and Cold War displacement, Boost targeted couples parked in secluded areas around Düsseldorf across a three-year span in the 1950s. What distinguished him was not scale alone but the apparent purposefulness of his methods — the attacks were staged, masked, and executed in partnership with an accomplice whom witnesses and observers described as being under Boost's near-total psychological influence. Only one killing was legally proven at trial, yet the circumstantial record across multiple incidents was consistent enough to shape his lasting reputation. His courtroom demeanor, described as quietly charismatic rather than visibly threatening, added a layer of unease that the evidence itself did not fully resolve.

Few figures illustrate the revolution devouring its own architects as clearly as Robespierre. His ascent through the Committee of Public Safety coincided with the Reign of Terror, a period in which ideological purity became grounds for the guillotine, and thousands were executed in the name of republican virtue. He combined genuine conviction with an institutional authority that made dissent dangerous, and the same logic he applied to enemies of the Revolution was ultimately turned against him.