Scripps operated in a realm of particular vulnerability, targeting tourists in transit — people with no local connections, whose disappearances might take time to register. The method of concealment was systematic enough to earn a grim nickname from investigators, and the geographic spread of his crimes across Southeast Asia complicated jurisdictional response. His arrest came only because he returned to Singapore, placing himself within reach of the authorities investigating a murder he had already committed there.

Few careers in modern science produce so stark a duality: the same mind that developed a process to feed billions also directed the first large-scale deployment of poison gas as a weapon of war. His work on chlorine at Ypres opened a new chapter in industrialized killing, and the pesticide derived from his research was later turned toward the murder of more than a million people in the Holocaust — including members of his own family. The Nobel Prize he received sits alongside that record, making him one of the more genuinely difficult figures in the history of chemistry.