REUTERS -- A leading Nazi hunter visited Copenhagen on Monday to request a police investigation into whether a Danish man was an accomplice in the murder of Jews at a camp in Nazi-occupied Belarus during World War Two.

The Dane has admitted to working as a guard at the concentration camp near Babruysk, Belarus in 1943 and witnessing executions of Jews there, according to a Danish police report from 1945 that was published in a book last year.

"He has admitted to being there. He has admitted seeing the atrocities," Efraim Zuroff, responsible for Nazi war crime investigations at the Simon Wiesenthal Center, told Reuters by telephone from London while en route to Copenhagen.

"He has never been prosecuted and I think he is in good health. There is no reason why it should be ignored."

There was no immediate Danish police or judicial comment on Zuroff's request.

Danish media said the man in question was 90 years old and had recently denied wrongdoing when asked about his past by reporters from the newspaper Berlingske Tidende.

Last week, a 94-year-old German man known as the "bookkeeper of Auschwitz", Oskar Groening, was sentenced to four years in prison for his role in the murder of 300,000 people at the Nazi death camp. It was seen as one of the last Holocaust trials due to the advanced age and ill health of any surviving suspects.

"If you heard the reactions of the survivors in the Groening case, and their sense of relief and joy in a certain sense that he was convicted, that is a very good reason why the victims of Mr. X certainly deserve the same satisfaction and apology," Zuroff said, referring to the Danish man.

Up to 1,000 Danes serving in Nazi Germany's armed forces worked in the Babruysk camp from the autumn of 1942 to spring of 1943 during which at least 1,400 Jewish prisoners died, according to a book published last year by historians Dennis Larsen and Therkel Straede.

Denmark was occupied by Nazi Germany from April 1940 until May 1945, during which around 6,000 Danes volunteered as soldiers for Hitler's Wehrmacht on the eastern front. At the same time, around 20,000 Danes joined the anti-Nazi resistance.