THE 93-year-old sister of accused war criminal Charles Zentai, who hoped her rare first-hand account of his wartime activities could help him avoid extradition to face a murder charge, has died.

The death of Julia Nikoletti at a Perth nursing home last year left just one known witness who could verify Mr Zentai's claim that he led a convoy out of Budapest on November 7, 1944, the day before he is accused of beating teenage jew Peter Balazs to death at the city's Arena Utza barracks.

That witness - octogenarian Stefi Fonyodi of Budafok, Hungary - has revealed that she cannot remember the date on which she left Budapest with Mr Zentai, a warrant officer in the Hitler-aligned Hungarian army.

The date of the convoy's departure was not clear either to Ms Nikoletti, who was in the same convoy. But both women backed Mr Zentai's claim that the two fellow soldiers later convicted of Balazs's murder - Lajos Nagy and Bela Mader - stayed behind.

Mr Zentai's son Ernie Steiner, who has been researching the case since 2005, said it was significant that both women corroborated that part of his father's story. Perth-based Mr Zentai, 87, is fighting extradition to Hungary, where he would be tried in a military court for the murder of Balazs.

Mr Zentai maintains Nagy and Mader were back in Budapest and running the barracks on the day Balazs was killed there. Mr Zentai was implicated in the personal documents of Balazs's father Deszo, a Budafok lawyer. They included testimony from the 1947 and 1948 trials of Nagy and Mader at the Budapest People's Court.

The Hungarian Government requested Mr Zentai's extradition after lobbying by the Jewish human rights group, the Simon Weisenthal Centre.

Ms Nikoletti first came to the defence of her younger brother in an interview with The Australian in 2005, when she said she left Budapest with him, their mother and his military transport unit in the first few days of November, 1944.

In 2007 she made a DVD of her memories of that time in case it was needed after her death. Ms Nikoletti told how Russian forces were advancing as they fled and, in the nearby town of Isaszeg some of her friends who stayed behind were raped and committed suicide.

theaustralian.news.com.au