His killings went unsolved for decades in part because he deliberately operated across jurisdictions he had no connection to, varied his methods, and left investigators with little to link the crimes together. The window in which he killed — a brief period of parole between lengthy incarcerations for sex offenses — made him a difficult target, and the forensic technology needed to identify him simply did not yet exist. When DNA evidence finally closed the cases in 2007, he had already been imprisoned for twenty-five years on unrelated charges, having chosen to remain behind bars voluntarily.

Over the course of three years in 1980s Paris, he carried out a sustained campaign of violence against elderly women living alone, targeting those he perceived as the most physically vulnerable. The murders were concentrated in the 18th arrondissement and surrounding areas, and their brutality — suffocation, beating, the use of plastic bags — drew sustained police attention without yielding an arrest for years. His eventual capture came not through investigative breakthrough but through the survival of a victim he believed he had killed. He died in prison custody before trial, leaving the legal record incomplete.

Kakehi targeted a succession of romantic partners over many years, exploiting the intimacy of those relationships to administer cyanide — a method that went undetected long enough to raise suspicion in at least ten deaths before her arrest. The case drew particular attention in Japan for what it revealed about vulnerability within late-life partnerships and the mechanisms by which such crimes can go unexamined. Her trial was complicated by a retracted confession and a dementia defense, but Japan's Supreme Court ultimately found the evidence of deliberate, sustained intent too substantial to set aside.

His career as a pirate captain lasted little more than a year, built on a single act of opportunism — a mutiny in the Spice Islands that handed him a loaded ship and a share of its treasure. What followed was a methodical unraveling: a failed bid for pardon, arrest, escape, recapture, and ultimately the gallows at Execution Dock. The gibbet proved more lasting than the man; decades after his death, sailors invoked his name as a reason to distrust offers of amnesty, his fate serving as a cautionary fixed point in the folklore of the early eighteenth-century Atlantic.

All five murders were committed within roughly nine months, when Rissell was seventeen and eighteen years old, making him among the youngest known serial killers to operate at that scale in American criminal history. His case drew significant attention from FBI behavioral analysts in the late 1970s and early 1980s, as his willingness to discuss his crimes in detail contributed to foundational research into the psychology of serial offenders. The pattern of his crimes — concentrated within a single apartment complex and its surroundings — reflected both opportunism and a level of deliberate targeting that investigators found notable.