Gunther van Well, who served as West German ambassador in Washington from July 1984 until last week, has a documented Nazi past.

We have unearthed a Nazi Party membership card issued to van Well in September 1940. It shows the date and place of the future diplomat's birth: Oct. 15, 1922, at Osterrath, near Krefeld in the Rhineland. He was given party membership number 7767073.

According to van Well's official biography, provided by the embassy, he graduated from high school in 1941. The biography does not mention his party membership.

Van Well's tenure as Bonn's ambassador to the United States ended a few days ago, and he decided to retire. He is married to an American, and an embassy spokesman said the van Wells will probably remain in this country.

After several unsuccessful attempts to meet with the ambassador, we sent him a copy of his Nazi Party membership card through an aide. Van Well then issued this statement:

"This copy is known for 40 years. Party membership was never active because I was drafted in the Wehrmacht early 1941. This suspended membership. I was a soldier until the end of the war."

We have no evidence to contradict van Well's claim that he was not an active member of the Nazi Party. But several experts we consulted said they had never heard that party membership was suspended upon entry into the armed services.

His official biography states that he was on active service until 1945. After the war he studied at Bonn University, where he earned degrees in economics and law. He entered the diplomatic service in 1952 and after an assignment in the personnel office he was sent to the West German mission at the United Nations in New York in 1954. In 1962-63, he attended Harvard as a fellow at the Center for International Affairs, and was then assigned to the Tokyo embassy for four years.

After serving in various high-level posts at the foreign office in Bonn, van Well was named West Germany's U.N. ambassador in 1981.

Incidentally, a U.N. press release of June 5, 1981, noted that van Well presented his credentials there to U.N. Secretary General Kurt Waldheim. Now president of Austria, Waldheim has been accused of participating in German atrocities in the Balkans during the war and of lying to cover up his Nazi past. The Justice Department has placed Waldheim on a list of individuals who may not be admitted as private visitors to the United States.

Footnote: Two months ago, Bonn's consul general in Rio de Janeiro, Hans Joachim Dunker, acknowledged he is a former Nazi. He remains at his post despite the revelation.

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