Detectives are investigating what part Anton Husak, now living in a holiday resort in Wales, may have played in a Nazi death squad that murdered Jews in Eastern Europe.

But they have had trouble gathering evidence.

Home Affairs Correspondent Jon Silverman tracks Anton Husak down

Mr Husak was on a list of suspected war criminals supplied to the UK Government by the USSR in 1988.

He is specifically alleged to have taken part in three massacres killing thousands of Jews.

In an exclusive report for the BBC, Home Affairs Correspondent Jon Silverman found him at home in the resort of Aberporth, on the west coast of Wales, where he lives with his wife Myfanwy.

Myfanwy Husak greets Jon Silverman

Mr Husak refused to speak to the correspondent while his wife Myfanwy threatened the BBC crew with a walking stick.

During World War II, special mobile death squads slaughtered tens of thousands of Jews in the wake of the German army advance.

In southern Ukraine they were helped by non-German volunteers in the Caucasian republics of Georgia and Armenia.

Records show the Caucasian company took part in liquidation of a labour camp at Kamionke on 10 July 1943, when 5,000 Jews were murdered in a single day.

Anton Husak is being questioned about that day by detectives.

Sam Halpern witnessed the massacre

One of few witnesses of the massacre, Sam Halpern, now living in New Jersey, was in the camp on the day, escaping hours before the massacre.

He hid nearby and witnessed what happened.

"They just called in people, put them in place and shot them. It went on for hours and hours," he told the BBC.

However, he has not been interviewed by Scotland Yard.

The civil war in Georgia in the 1990s has hampered the war crimes investigation. Detectives recently went to the capital, Tiblisi, but had trouble finding eye-witnesses to Mr Husak's alleged involvement in the massacres.

Mr Husak is understood to have told Scotland Yard that, although he saw atrocities committed, he is innocent.

His file is with the Crown Prosecution Service.