Active for less than a month in the summer of 1987, Sergeev killed four people across Zaporizhzhia and Yalta while taunting investigators with handwritten notes and a recorded audio message left at crime scenes. The scale of the response to his brief spree — involving servicemen, aviation crews, and volunteers across hundreds of settlements — reflects both the public panic he generated and the difficulty Soviet authorities had in containing him. His attempt to claim insanity at trial, which included killing a fellow prisoner to strengthen the plea, was ultimately unsuccessful.

Santora operated near the center of some of the Bonanno family's most consequential internal violence during the late 1970s and early 1980s, playing a role in both the Galante execution and the triple-captain ambush of 1981 that effectively resolved a factional struggle for control of the family. His crew's entanglement with the Donnie Brasco operation — one of the FBI's most damaging infiltrations of the American Mafia — added a further layer of significance to his tenure, ultimately costing his own superior, Napolitano, his life on a contract Santora himself helped authorize.

What distinguished Demetrius "Big Meech" Flenory from many drug trafficking figures of his era was the scale of his operation's reach and its deliberate cultural embedding — BMF moved cocaine across multiple U.S. cities while simultaneously positioning itself within the hip-hop industry as a promotional and entertainment entity. The overlap between the organization's criminal infrastructure and its public-facing celebrity was not incidental but functional, serving to launder proceeds and build a kind of legitimacy that complicated law enforcement's approach. It ultimately took a federal Continuing Criminal Enterprise prosecution — a statute reserved for large-scale, ongoing criminal organizations — to dismantle what the DEA had been tracking for years.

His case is remembered as much for the failures that preceded it as for the violence itself — his mother's plea to her MP, asking whether her son would have to commit murder before receiving mental health intervention, went unanswered. Over two days in September 2004, Gonzalez attacked strangers across London and Sussex, killing four, driven by a stated desire to emulate fictional horror villains. The letters he wrote to himself afterward, describing the killings with satisfaction, document a psychology that institutions had been warned about and declined to address.