A former U.S. Army counter-intelligence officer said Thursday that he had "trustworthy" information 38 years ago that Nazi war criminal Josef Mengele was detained at least briefly by U.S. authorities in Vienna two years after World War II, according to a statement released here.

The Simon Wiesenthal Center said the statement was made by Benjamin J.M. Gorby, an attorney living in Tel Aviv. Gorby said he was stationed in Regensburg, Germany, when he received information about Mengele's possible arrest from a U.S. agent who had questioned a German informer.

The center has demanded that the U.S. government investigate any contact U.S. authorities might have had with Mengele in 1947 and again in 1962, when he reportedly applied in Argentina for a visa to Canada.

Mengele, who would be 73 if alive, was a physician and former major in the Nazi secret police and is wanted by West Germany on murder charges. Among his alleged crimes was gassing of concentration-camp prisoners.

The center, an international clearinghouse for information on war criminals believed to be at large, announced Wednesday that it had located a copy of Gorby's 1947 report to his Army superiors through a Freedom of Information Act request but could not find Gorby to confirm it.

Rabbi Marvin Hier, dean of the center, said today that William Perl, a Washington-area attorney who helped to rescue 40,000 European Jews before World War II, led them to Gorby in Israel, where he has lived since he left the Army.

Hier said he is particularly concerned that Gorby was working as part of an Army unit later found to have helped Nazi war criminals escape arrest and flee Germany in exchange for information about Soviet activities in Europe. In a statement that Hier said was dictated by Gorby on the telephone Thursday night, the former agent indicated that he did not know if his superiors acted on his Mengele report.

"There is no doubt that I considered my source of information that Mengele was arrested by the U.S. as fully trustworthy for, had I not thought so, . . . I would not have sent out such a memo to another detachment located in a foreign country Austria , nor would I have sought and obtained permission to do so by my commanding officer," Gorby said in the statement released by the center.

Gorby said he does not remember his source's name and was not authorized at the time to pursue the information personally.