Malmö Östra hospital murders
The Malmö Östra hospital murders were a Swedish case of serial senicide committed by the 18-year-old Anders Hansson at a hospital in Malmö between October 1978 and January 1979. Hansson poisoned elderly patients during his working hours as an orderly with the detergents Gevisol and Ivisol.
Source: Wikipedia — Malmö Östra hospital murders (CC BY-SA 4.0)