The court found him guilty of lying to cover his past and gain entry into the United States. It stripped him of his citizenship. Two years after his conviction, when deportation seemed imminent, a court of appeals ordered a new trial, which it said ''almost certainly'' would clear Mr. Walus. Nine months later the charges against him were dropped.

''They told me they made a mistake,'' he recalled. ''They told me I was not the person who did those things. They apologized. They told me to forget about it.'' Worked on German Farms

Mr. Walus tells all who will listen, as he told the court, that he was working on labor farms in Germany in the years when the crimes described by the Jewish witnesses were committed, 1939 to 1943. Federal Judge Julius Hoffman ruled that Mr. Walus won American citizenship by hiding a Nazi past.

The case against Mr. Walus, a Pole born in Germany, was dropped when lawyers dug up evidence that he had indeed been in Germany at the time in question. They also showed the Gestapo did not accept Poles, particularly ones as short as Mr. Walus, who stands 5 feet 4 inches.

''My neighbors treated me terribly,'' he said. ''They called me Nazi, Gestapo. They threw rocks at me.'' Mr. Walus said he no longer gets letters and telephone calls threatening his life, but he said the cost of his legal defense had ruined him financially. He lives quietly in retirement with his wife and one of his four children.