ZDF said Aribert Heim died of cancer
Aribert Heim, one of the most wanted Nazi criminals, has been dead since 1992, German's ZDF television reports.
It says Heim, known as Nazi Germany's "Doctor Death", lived under a pseudonym and died in Egypt's capital, Cairo.
ZDF says it found Heim's passport and other personal documents in a hotel where he lived.
Heim was a concentration camp doctor and was accused of killing hundreds of concentration camp victims in WWII, using horrific medical experiments.
In its report, ZDF quoted witnesses, including Heim's son, as confirming that he died in 1992.
The German TV channel also said Heim had converted to Islam.
Leading Nazi hunter Efraim Zuroff from the Simon Wiesenthal Centre said he had not seen the documents found by ZDF.
But he added that if confirmed, the news would be "earth shattering", the Associated Press reports.
Heim was one of the last major Nazi fugitives believed to be still at large.
He is accused of carrying out horrible medical experiments on prisoners of the Mauthausen concentration camp in Austria during World War II.
After the war he lived in West Germany, working as a doctor.
He disappeared in 1962 when police opened an investigation into his past.