March 15, 2007 8:58 AM

BELGRADE, Serbia-World War II archives in Belgrade and assistance from Serbian authorities are essential to efforts to prosecute a Hungarian man and two Croats believed responsible for wartime killings of thousands of Jews, Serbs and others, a Nazi hunter said Thursday.

Efraim Zuroff of the Simon Wiesenthal Center spoke after meeting with President Boris Tadic and Prime Minister Vojislav Kostunica about the Center's "Operation: Last Chance," aimed at bringing to justice hundreds of Nazi war crimes suspects still alive.

Zuroff said the Serbian leaders pledged to provide documents and contact witnesses relevant for the WWII atrocities during the Nazi occupation of the former Yugoslavia. The atrocities included the so-called Great Raid of 1942, when some 800 Jews and 400 Serbs were rounded up, shot and drowned in the freezing Danube river in the northern city of Novi Sad.

The area was controlled by pro-Nazi Hungarians at the time. Zuroff said one of those allegedly responsible was Sandor Kepiro, now 93. Kepiro, who was a gendarmerie lieutenant in Novi Sad at the time, migrated to Argentina after the war but returned to Hungary in 1996.

Hungarian prosecutors recently opened an investigation into Kepiro following demands by the Wiesenthal Center and after researchers in Belgrade found a copy of a 1944 Hungarian court verdict that found him guilty of disloyalty to Hungary.

"The criminal investigation has finally begun. Kepiro should be convicted and justice finally achieved," Zuroff said. But he warned that time may be running out due to Kepiro's age.

Kepiro has denied the accusations, saying he was a scapegoat in a show trial.

Last month, the Budapest Municipal Court said the 1944 ruling sentencing Kepiro to 10 years in prison could not be enforced because a retrial shortly afterward annulled the sentence.

"It is important to get this guy into court ... and send him where he belongs," Zuroff said, adding he expects "many more relevant documents" from the Belgrade-based Museum of Genocide "which contains invaluable papers and evidence" about WWII atrocities in the Balkans.

During a previous visit, Zuroff criticized Serbian officials for not doing enough about Kepiro and two other Nazi-era suspects, Croatians Milivoj Asner and Ivo Rojnica.

Asner and Rojnica are accused of being involved in atrocities during Croatia's wartime Nazi puppet regime, which persecuted tens of thousands of Jews, Gypsies and Serbs.

Kostunica said in a statement that Serbia's judiciary will "do everything to gather evidence and (enable) access to witnesses" in the three cases.

Rojnica is believed to be living in Argentina while Asner is in Austria, where authorities recently said he was unfit to stand trial.

Serbia itself stands accused of numerous atrocities committed during the 1990s breakup of the former Yugoslavia and remains under Western pressure to hand over fugitive suspects to a U.N. court.

"We are well aware of problems facing Serbia at the moment," Zuroff said, but "I am cautiously optimistic that Serbia will become more involved" regarding the case of Kepiro, Asner and Rojnica.