A senior academic at an Israeli university is claiming to have a family connection to Adolf Hitler.
Michael Mach, of Tel Aviv University's Department of Philosophy, told the JC that his grandmother, Erna, married Hans Hitler after divorcing his grandfather.
Hans Hitler, he claimed, was Hitler's nephew - the illegitimate child of the German leader's half-brother, Alois Jr.
Last week Dr Mach, who is a German-born convert to Orthodox Judaism, told The Guardian that he met Hans Hitler only once, aged 12, when his grandparents came to tea.
"Hans was a very nice man," he told the paper, which did not name him. "No passions, no brutality."
However, the Holocaust authorities approached by the JC could find no record of a Hans Hitler.
According to Ben Barkow, director of the Wiener Library, the London-based Holocaust archive, Alois Jr had two legitimate sons: William Patrick Hitler, who emigrated to America, and Heinz Hitler, reportedly Hitler's favourite nephew, who was killed on the Russian front during the Second World War.
But there is no reference, in any serious Holocaust history, to another illegitimate son.
The Holocaust Museum in Washington said it had "no information" on a Hans Hitler or an Erna Hitler, although it could not exclude the possibility of their existence. And Yad Vashem, in Jerusalem, said its historians had never heard of Hans Hitler, and that a full archival check brought up no reference to the couple.
Confronted by the JC, Dr Mach stood by his story.
"There are a lot of things that Yad Vashem doesn't know," he said. "They don't know the names of more than three million of the Jews who perished in the Holocaust. But I can promise you that if they check the records in the city of Hamburg, they will discover that there was a Hans Hitler who died about 25 years ago."
Dr Mach said he did not have copies of the documents to prove the claim, "nor do I want to prove the claim".
His story has been widely reported, including in Israel's Yediot Achronot and Ha'aretz dailies, as well as in The Guardian last week.
In 2006, Dr Mach told the American Orthodox Union's Jewish Action magazine - again anonymously - that "what my step-grandfather lacked in vitriol was more than made up by the fierceness of my grandmother who was a sworn Nazi. She believed in the Nazi ideology before, during and even after the War. She was proud that her father-in-law was Hitler's brother, although he kept away from politics.
"Instead, he managed a café in Berlin, and because everyone knew that he was the Fuhrer's brother, all the Nazi elite patronized his establishment. This made his family and him - including my grandparents - local ‘nobility'."
However, Dr Mach emphasised to the JC that he resented the headlines which implied he was related to Adolf Hitler. "You cannot say I am related to Hitler because my grandmother happened to divorce my grandfather and subsequently marry a half-nephew of Adolf Hitler. It's nonsense to say I am related."