Documents have surfaced in Egypt showing the world's most-wanted Nazi war criminal, concentration camp doctor Aribert Heim, died in Cairo in 1992, Germany's ZDF television and The New York Times reported.

Wednesday's reports said Heim, known as 'Dr. Death,' was living under a pseudonym and had converted to Islam by the time of his death from intestinal cancer.

ZDF said that in a joint effort with the New York Times, it located a passport, application for a residence permit, bank slips, personal letters and medical papers — in all more than 100 documents — left behind by Heim in a briefcase in the hotel room where he lived under the name Tarek Hussein Farid.

Though he did not know Heim's real identity, Egyptian dentist Tarek Abdelmoneim el Rifai said he knew him through his father, Abdelmoneim el Rifai, 88, who was Heim's dentist in Cairo.

He told the AP on Wednesday that he only met Heim a few times, 20 years ago, but confirmed that he knew of his death.

"He died in 1992. I didn't know that he was a doctor and that he is the most wanted Nazi war criminal. I am surprised," he said in a telephone interview.

"He introduced himself to my father as a German and I know that he converted to Islam and changed his name."

When he met Heim two decades ago at his father's clinic, el Rifai said he had the impression he was on the run.

"The only thing I knew about him is that he fled from the Jews," el Rifai said.

ZDF quoted Heim's son Ruediger Heim as confirming the pseudonym Tarek Hussein Farid as his father's assumed name and the documents as belonging to him. Heim said he visited his father regularly in Cairo and had taken care of him after an operation related to his cancer in 1990.

Simon Wiesenthal Center head Nazi hunter Efraim Zuroff said he has not seen the documents and that while it seems that there is "definitely a strong possibility" they point to Heim's death in Cairo 16 years ago, they need to be examined by experts.

If it turns out to be true, however, he said that "the German police have a very important investigation on their hands in terms of prosecuting people who helped Aribert Heim escape justice."

He pointed out that Ruediger Heim has previously said that the only contact he had since his father went into hiding in 1962 were two notes that appeared in his family's mailbox, and that he had no idea if he was alive or dead.

"Ruediger has been lying," Zuroff told The Associated Press in an interview from Jerusalem. "Either he is lying now or he was lying before, and he has a vested interest in this so anything he says has to be taken with a certain amount of skepticism and suspicion — and the most important thing is missing: the body. There's no grave, there's no corpse, there's no DNA tests."

Ruediger Heim refused to comment on the discrepancies in what he has said, or on the assertion that his father had died in 1992, when contacted at his home by the AP.

"The whole story is very emotional, and I'm not able to say anything at this time," he said.

ZDF reported that Heim was buried in a cemetery for the poor in Cairo, where graves are reused after several years "so that the chance of finding remains is unlikely."

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.

In 1961, German authorities were alerted that Heim was living in Baden-Baden and began an investigation, but when they finally went to arrest him in September 1962, they just missed him — he apparently had been tipped off.

Heim would be 94 today if still alive.

Heim fled through France and Spain before crossing into Morocco, and eventually settling in Egypt, ZDF and the Times reported, citing Ruediger Heim.

He lived in Cairo at the Kasr el Madina hotel for the 10 years leading up to his death, the report said.

Ruediger Heim told ZDF that he first visited his father in 1976, organizing the visit through his aunt and arranging to meet with him in a hotel.

"He recognized me right away," Heim recalled. "It was a meeting of worlds. I was there for 14 days."

But, he said, he did not talk with his father about the allegations against him — largely because he said he wasn't fully aware of them himself.

"I didn't ask him 'how many people did you kill' because I didn't know, I didn't know any concrete details," he told ZDF. "Later, on other visits, I got to know his life better."