Pressure is mounting on an Australian man to prove that his remarkable Holocaust survival story is true.

Alex Kurzem’s story has been told in a bestselling book and an award-winning documentary — both titled The Mascot — but it was the feature that was screened on America’s 60 Minutes in 2009 that roused the suspicions of Dr Barry Resnick, a Californian college professor who lost relatives in the Holocaust.

Uldis (Alex) Kurzem claimed he witnessed the massacre of his Jewish mother, sister and brother in the Belorussian village of Koidanov as a five-year-old boy in 1941. He also claimed he was later adopted by a Latvian guard who took pity on him, gave him a new name (Uldis Kurzemnieks) and made him his battalion’s mascot. Dressed in SS regalia, he was feted in a Nazi propaganda film as “the Reich’s youngest Nazi”.

The Mascot received critical acclaim. But not everyone was impressed. “After watching the broadcast and reading the book, I had serious doubts,” Dr Resnick said. “One historian told me there is nothing unusual about Kurzem’s story of being a mascot for a military unit. However, when he claims to be Jewish and was picked up by the Nazis, it then becomes a blockbuster of a story.”

Dr Resnick has been working for the past three years with DNA specialist Dr Colleen Fitzpatrick, who was involved in uncovering two Holocaust fraud stories — Surviving with Wolves by Misha Defonseca and Angel at the Fence by Herman Rosenblat.

Mr Kurzem, who immigrated in 1949 and lives in Melbourne, believes he was born Ilya Galperin, the son of Solomon Galperin, who was taken to Auschwitz but survived, remarried and had another son, Erik.

The American scholars believe the only way to conclusively prove this is for Mr Kurzem and Mr Galperin to take a DNA test.

But Mr Kurzem, who stands by his story, said: “They call me a liar, a fake. Would you co-operate with people like that? If she [Fitzpatrick] had asked in a nice way… I would’ve done it.” Nevertheless, he said he would take the test to “shut them up”. “I will prove them wrong,” he said.

Mr Kurzem’s story is also under investigation by the Claims Conference, executive vice president Greg Schneider confirmed. “No proof of fraud has been found and, as such, we have not withheld any payments,” Mr Schneider wrote in an email.

In addition, survivors at the Jewish Holocaust Centre in Melbourne are dubious about some of his claims.

Phillip Maisel, who has recorded some 2000 testimonies, did not believe the entire story when he first interviewed Mr Kurzem in 1996.

He disputed that the massacre of Koidanov took two days. “It was done in one afternoon and this is confirmed in a Yizkor book of Koidanov containing letters to relatives from the few who survived,” Mr Maisel said.

“They’re accusing me and sentencing me,” Mr Kurzem said. “I’m a million per cent sure I am Jewish. I wish I wasn’t when I was a little boy. It was a curse. Now it’s big evidence,” he said.

But Dr Resnick added. “Even if Mr Kurzem is Jewish did he witness the massacre of his family? Is he Ilya Galperin? A DNA test is the only way to prove this story.”