Callisto
Hellenismos, BTW
Joseph Mengele was the dbag "chief medical officer" at Auschwitz who committed "experiments" on prisoners, notably on juvenile twins, like unnecessary amputations, infecting them with typhoid and other diseases. Among other atrocities. He personally was involved in hundreds of thousands of deaths. He was called Todesengel (English: Angel of Death). The coward fled to Argentina.Manson, Gacy, Bundy.
Howard Shipman was more recent, he died 18 years ago. Another medical doctor (GP), he killed several patients, close to 300 of them. Most were elderly, though he's suspected of killing some children.