Heim, nicknamed Dr Death for killing hundreds of inmates at Mauthausen concentration camp in
An Austrian doctor with Adolf Hitler's dreaded police unit the SS, Heim removed organs from victims without anaesthetic. He even kept the skull of one man he decapitated as a paperweight.
Mr Zuroff, director of the Simon Wiesenthal Centre in
"He is the most important war criminal most likely to be alive. He murdered ... tortured hundreds of inmates, he used body parts for experiments. In that respect you could say he's a symbol of the Nazi's perversion of science, of medicine."
At age 93, the time to catch Heim is running out. "Our fear is that one of the worst criminals of the Holocaust ... will have eluded justice," Mr Zuroff said.
"This is something that will only encourage future genocide and mass murderers, and something which we find to be a travesty of justice."