The former dentist of Hamas leader Yahya Sinwar has revealed his nephew is among the hostages abducted by the terror group on October 7.

Dr Yuval Bitton was a dentist at the Israeli prison where Sinwar was incarcerated for murder until 2011.

Speaking to German outlet Bild, Bitton revealed he was related to Tamir Adar, 38, and his grandmother Yaffa Adar, 85, who were kidnapped from Kibbutz Nir Oz. Bitton’s nephew Tamir is the father of two small children, who survived the attacks on October 7.

The massacre was largely planned by Sinwar, 61, who was serving a life sentence in Nafha Prison before being released as part of a prisoner exchange for Israeli soldier Gilad Shalit in 2011.

Yahya Sinwar, Hamas' political chief in Gaza (Photo: Getty)

It was at Nafha Prison where Bitton, who worked first as a dentist and then as head of the Israeli Prison Service intelligence division, came to know the notorious terrorist group leader.

Bitton said: “I was against Sinwar being released. I spent a lot of time with him, [and] it was clear to me that he would rise to the top within Hamas.

“I know how cruel he is, I have never underestimated his abilities. But unfortunately, others have. He knows us very well, he follows Israeli society, our politics, our debates.”

Bitton said Sinwar, who was incarcerated at Nafha for 22 years, learned Hebrew and studied Israeli history and politics while in prison.

During a medical check-up at the prison in 2004, doctors also discovered that Sinwar had a brain tumour and, in 2008, they were able to surgically remove it.

Speaking to The Mirror in another interview, Bitton said: “The fact that we saved his life cost hundreds of children and old people their lives. We later discovered that my nephew is now in Gaza, a captive of the man whose life we saved.

“That was Sinwar’s way of saying thank you to us. If I was ever to see this man again face to face, I would say, ‘Only you, Yahya Sinwar, have the blood of your brothers and sisters in the Gaza Strip on your hands.’”