Aribert Heim

Aribert Heim is a former Nazi doctor who allegedly murdered hundreds of people at Mauthausen concentration camp during the process of performing needless experimental surgeries, often without anesthetic. In July 2008, Nazi hunter Efraim Zuroff headed to South America to try to locate the doctor, who is believed to still be alive.The New York Times: Nazi Hunters In Chile Seeking Mauthausen "Dr Death" (July 7, 2008)

While a doctor at the Austrian concentration camp Mauthausen, Heim is believed to have performed hundreds of gruesome medical experiments on living prisoners. Heim is alleged to have injected poison into the hearts of his victims, while they were still alive, and without using anesthetic. He would then allegedly time how long it took the victims to die using a stopwatch. Heim also reportedly decapitated one of his victims and kept the man's skull as a paperweight.The New York Times: Nazi Hunters In Chile Seeking Mauthausen "Dr Death" (July 7, 2008)