The hunt for Heim has taken investigators from the German state of Baden-Wuerttemberg all around the world. Besides his home country of Austria and neighboring Germany where he settled after the war, tips have come from Uruguay in 1998, Spain, Switzerland and Chile in 2005, and Brazil in 2006, said Heinz Heister, presiding judge of the Baden-Baden state court, where Heim was indicted in absentia on hundreds of counts of murder in 1979.
Thousands of German war criminals were prosecuted in West Germany after World War II. In the 1970s Western democracies began a hunt in earnest for Eastern European collaborators who had fled West claiming to be refugees.
"All of a sudden there was pressure on countries like Latvia and Estonia to put these people on trial," Zuroff said. "So two times in the past 30 years we've been given a tremendous infusion of new energy and new possibilities."
The Wiesenthal Center's previous annual survey counted 1,019 investigations under way worldwide. The number is lower this year and inexact because not all countries responded, but new investigations were up from 63 to 202, Zuroff said.
Still, a lack of political will in many countries, and what Zuroff called the "misplaced-sympathy syndrome" — reluctance to pursue aging suspects — has meant that few people have been brought to trial and convicted.
Lotter, the witness to Heim's atrocity, was in Mauthausen. His statement from the 1950 arrest warrant was viewed by the AP at the National Archives in College Park, Md.
Now that the necessary evidence is in place, numerous witness statements have been taken and Heim has been indicted, all that's left is to find him.
Born June 28, 1914 in Radkersburg, Austria, Heim joined the local Nazi party in 1935, three years before Austria was bloodlessly annexed by Germany.
He later joined the Waffen SS and was assigned to Mauthausen, a concentration camp near Linz, Austria, as a camp doctor in October and November 1941.
While there, witnesses told investigators, he worked closely with SS pharmacist Erich Wasicky on such gruesome experiments as injecting various solutions into Jewish prisoners' hearts to see which killed them the fastest.
But while Wasicky was brought to trial by an American Military Tribunal in 1946 and sentenced to death, along with other camp medical personnel and commanders, Heim, who was a POW in American custody, was not among them.