For Nazi hunter Ephraim Zuroff, it is the end of a long court battle - but for Sandor Kepiro, Mr Zuroff's accuser in the libel stand-off that ended this week, the beginning of another.

On Tuesday, a Budapest court acquitted Mr Zuroff, director of the Simon Weisenthal Centre in Israel, of libel for describing Sandor Kepiro, a former officer in the Hungarian Gendarmerie, as a war criminal.

But in a move that has baffled legal experts, Kepiro was scheduled by Hungarian legal authorities to face trial for war crimes in Budapest Municipal Court on Thursday, just two days after the conclusion of the libel case. David Allen Green, media lawyer at Preiskel & Co, said: "It is unusual for any libel claim to precede a related criminal case."

Mr Kepiro, 97, who lives in Budapest opposite a synagogue, faces charges of commanding a patrol whose members killed four civilians in Novi Sad, northern Serbia, in January 1942 after the area was occupied by Hungary. Irene Weisz, one of the victims, was shot in her bed, according to court papers.

In 2006, Mr Zuroff submitted documents to the Hungarian courts regarding Kepiro's alleged role in the murders of 1,246 civilians in Novi Sad, which prompted Kepiro to sue for libel.

Mr Zuroff said: "This has been a long and frustrating process, which began in the summer of 2006, but I am hopeful that justice will finally be achieved. That is what the victims of the massacre in Novi Sad deserve and that is what I have been fighting for from the very beginning of this process."

Hundreds of civilians, including Jews, Gypsies and Serbs, were shot in the Novi Sad massacres, which lasted for several days. Victims were lined up on the bank of the Danube and shot. The killings were halted only when senior officers arrived from Budapest.

Mr Kepiro was sentenced in 1944 to ten years for his role in the massacre but the verdict was later annulled. He denied any involvement and said that his role was only to check the names of the people being rounded up. He fled Hungary for Argentina in 1945 and returned to Budapest in 1996 when Mr Zuroff discovered his whereabouts. The Hungarian authorities re-opened the case after the Simon Weisenthal Centre put him on top of its list of alleged Nazi war criminals.

Peter Feldmajer, the president of the Hungarian Jewish Community, accused the Hungarian authorities of procrastination and delays. Documents from 1944 had been submitted to the Budapest prosecutor's office in 2009. "Nobody wanted to work on this case. It is a scandal," he said.

Nazi war criminals are still not being brought to justice in nine countries, the Simon Weisenthal Centre said. The centre's annual report on efforts to track down perpetrators said that Austria, Canada, Estonia, Latvia, Lithuania, Norway, Sweden, Syria and Ukraine were failing in their duties.