Jacoob Ben Nistell, aka "Yaakav" - a practicing rabbi in the western city of Poznan - has gone missing after Polish media discovered that he was, in fact, neither a rabbi nor Jewish.

"I know him, but that's no Nistell but Jacek Niszczota. He's from Ciechanow," an anonymous caller to the television channel TVN24 said after the story broke in Poland.

"Yaakav" admitted two weeks ago during an interview with a local paper that he is not a rabbi after someone from his hometown recognized him and informed the paper.

Krzysztof Kazmierczak, a reporter for the paper "Glos Wielkopolski" reported that the alleged rabbi is, in fact, a Catholic cook named Jacek Niszczota from Ciechanow, a town in north-central Poland.

Have faith

"Yaakav's" Facebook page uses the name Yaakav Ben Nistell and says he is from Haifa, in Israel. It is not clear if Ben Nistell ever visited or lived in Israel.

He led activities for children and young people about Judaism in Poznan and participated in ecumenical prayer services with Polish bishops. He also reportedly held interfaith meetings with priests and imams on behalf of the local Jewish community.

The deception was not discovered by the board of the Poznan branch of the Union of Jewish Religious Communities in Poland.

Alicja Kobus, president of Poznan's Jewish community, told AFP that no one had thought to check the rabbi's identity.

"I'm surprised. I never checked his identity document. He said he comes from Haifa, his mother still lives there, and he has an Israeli passport and a son in the army. I believed that he is who he says he is because of how he looked and that he was able to pray in Hebrew and knew Jewish customs," Kobus told "Glos Wielkopolski."

"I admire his determination - he had learnt Hebrew, the Jewish traditions and prayers, all through listening to Israeli radio," she said. She bore him no ill will, she added, as he had never accepted any money for his work with the community.

His dark beard and side locks must have been dyed, she said, as they later found out that Jacek Niszczota was in fact blond.

Asked by phone by a TVN24 journalist about the name Jacek Niszczota, "Yaakav" reportedly appeared taken aback and said he had to go the store and "would back in 10 minutes." He has now apparently disappeared from Poznan.

Poznan's Jewish community was one of the earliest to be established in Poland. The first reference to Jews living in the town comes from 1379. Tradition dates the town's synagogue to 1367, and the cemetery to 1438.