By THE ASSOCIATED PRESS

Filed at 3:55 p.m. ET

JERUSALEM (AP) -- A Nazi war criminal notorious for sadistic experiments that killed hundreds of prisoners during World War II has been tracked to Spain , according to media reports Saturday. Spanish police said they had not yet found the man.

The German weekly Der Spiegel said Spanish investigators believe the 91-year-old suspect, Aribert Heim, has been in Spain recently.

During the war, Heim earned the nickname ''Dr. Death'' for experimenting on inmates at the Buchanwald and Mauthausen camps. His research included performing surgery without anesthesia and injecting prisoners with gasoline, poison and lethal drugs to see how much their bodies could take before dying, the Israeli newspaper Haaretz said.

Heim has been a fugitive since he was charged by German authorities in 1962 with killing hundreds of concentration inmates in Germany and Austria with lethal injections. He is thought to have evaded capture in Germany, Argentina , Denmark , Brazil and Spain.

Spanish police said they had not found Heim during searches after receiving indications that he was living in the northeastern province of Girona.

''We haven't detained anyone with that name,'' said Joan Lopez, a police spokesman in Girona. ''All we know is that he may have been in the area of Palafrugell recently.''

Efraim Zuroff, Israel director of the Nazi watchdog Simon Wiesenthal Center, said the search for Heim intensified a year and a half ago when the German government discovered a bank account in his name and set up a task force to find him.

It was not clear if Heim was still in Spain, he said.

''There's some speculation that he might have escaped to other countries,'' Zuroff said.

Der Spiegel said Spain was suspected as a possible hiding place for Heim as long ago as the mid-1980s and there had been increasing indications in recent weeks that he might have until recently lived somewhere near Denia on the Mediterranean coast.

Although Heim never completed medical training after studying at the University of Vienna, after the war he worked as a doctor in southern Germany until he was indicted. German authorities have offered a $159,000 reward for his arrest and the Wiesenthal Center $12,200.