The former dentist of Hamas leader Yahya Sinwar has described him as a “cruel” mastermind who recruited countless Palestinians to his cause while languishing in an Israeli prison.

Speaking to German tabloid Bild, Yuval Biton recounted how he treated Sinwar while working as a dentist at the jail where the Hamas chief was sequestered in the late 1990s.

“I spent a lot of time with him...it was clear to me that he would rise to the very top within Hamas,” said Dr Biton, describing Sinwar as a charismatic but menacing figure.

“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.”

Dangerous

Sinwar, 61, spent 22 years in Israeli prisons on terrorism offences, and took advantage of his imprisonment to learn fluent Hebrew and gain a deep understanding of Israeli culture and society.

He quickly rose through the ranks of Hamas and was released from prison in 2011 as part of the Shalit prisoner exchange. Dr Biton said he was against this at the time as he felt Sinwar was dangerous.

“Even back then, you could tell the difference between Hamas members from Gaza and those from the West Bank,”  he said. 

Sinwar, who was born in Gaza’s Khan Younis refugee camp, was clearly part of the more radical former group, he said, which was uninterested in compromises with Israel.

In one significant incident, Sinwar was asked shortly before his release to sign some papers renouncing terrorism.

“He asked what it was...then he refused to sign the paper, and all subsequent Hamas prisoners then refused as well,” Dr Biton recalled. All of them were released anyway.

Hamas massacre

Ironically, Israeli media reports have claimed that during his imprisonment Sinwar received surgery for an illness – a brain tumour, according to one former official – that saved his life. He would go on, years later, to serve as one of the masterminds behind the October 7 Hamas massacre.

Nearly three decades after being Sinwar’s prison dentist, the roles have been reversed: now Sinwar and his men are the captors of Dr Biton’s nephew, Tamir, who was dragged to Gaza during the massacre.

“I know very well what these people are capable of...but I didn’t think it would affect me personally,” he said.