Within days of the 7 October attacks last year, Israeli investigators identified Yahya Sinwar, then the military leader of Hamas in Gaza, as the mastermind of the surprise attack on Israel.
To their increasing astonishment, they learned that Sinwar had not just conceived of what he had called “Operation al-Aqsa Flood”, but that he had planned and organised the assault almost alone. Only a handful of close aides had been let in on the plans, some with only days to go before the attack, which led to the killings of about 1,200 people, mostly civilians, the abduction of more than 250, and triggered an Israeli offensive that has so far killed more than 42,000 and laid waste to swathes of Gaza.
His unremitting and ruthless commitment to the cause of Hamas – and to violence – marked the decades-long career of Sinwar.
Born in a refugee camp in Khan Younis, in the south of Gaza, to parents who had been forced to flee their homes in what became Israel in 1948, Sinwar was drawn into Islamist activism as a teenager. Across the Middle East, a religious resurgence had gathered momentum over the previous decade, and Sinwar, then a science student at the Islamic University of Gaza in the early 1980s, was drawn to Ahmed Yasin, a charismatic, severely disabled cleric who set up a local branch of the Muslim Brotherhood.
In 1987, Sinwar was drafted by Yasin into the newly-created group Hamas, and made head of its nascent intelligence service. Duties included uncovering and punishing spies or other “collaborators” with Israel as well as people in Gaza who infringed Hamas’s strict “morality” codes. This Sinwar accomplished with implacable determination, confessing later to murdering at least 12 Palestinians.
Arrested in 1988 and sentenced to four life sentences for attempted murder and sabotage, he spent 23 years in Israeli jails. In prison, Sinwar refused to talk to any Israelis and personally punished those who did, pressing the face of one into a makeshift stove, according to one Israeli former interrogator who worked at the institution where Sinwar was held. He also made repeated efforts to escape.
“He’s 1,000% committed and 1,000% violent, a very, very hard man,” said the interrogator.”
But Sinwar was also a sophisticated political operator with a sharp mind who decided to use his time in prison to learn Hebrew and study his enemy. On several occasions, Sinwar organised strikes in prison to improve working conditions, and survived brain cancer in 2008 after being treated by Israeli doctors. Sinwar also wrote a semi-autobiographical novel, describing life and militancy in Gaza.
Though he would be among the more than 1,000 prisoners to be swapped in 2011 for Gilad Shalit, an Israeli soldier captured by Hamas five years earlier, Sinwar rejected the deal. It went ahead anyway, and Sinwar, back in Gaza, returned to frontline militancy immediately. A journalist who met him at the time told the Guardian the Hamas leader was so focused it was like “the world didn’t exist beyond his eyeballs”.
In Gaza, where Hamas had seized power four years earlier, Sinwar married, had children and rapidly began to build a personal following. He crushed a bid by independent jihadists to establish a bridgehead in the territory and is widely believed to be behind the 2016 killing of another senior Hamas commander, Mahmoud Ishtewi, in an internal power struggle.
With his reputation for ruthless competence well established, Sinwar assumed the overall command of Hamas in Gaza in 2018, consolidating relations between the organisation’s military and civil administrative wings and steadily marginalising the political leadership overseas.
Convinced that the capture of Israeli soldiers was the “only way” to free prisoners”, a task he saw as central to his view of the role of Hamas, Sinwar began to plan a major operation to provide bargaining chips to release Palestinians from Israeli jails.
Quite when he conceived of what became the 7 October attacks is unclear, but versions may have been considered over many years. In 2022, Israel got hold of a Hamas plan for a major attack through the fence, codenamed Jericho Wall. Despite its significance, the plan was filed away because officials believed the group was incapable of such an operation.
Sinwar also threw up a smokescreen, lulling Israel into false security with public statements that could mislead, sometimes by coming close to telling the truth.
In 2022, Hamas produced a TV series called Fist of the Free, which depicted its militants raiding Israel en masse. Sinwar gave out prizes to all those involved at a public ceremony, praising in a speech the accuracy of the series and saying that that their work was “an integral part of what we’re preparing”.
Analysts are divided over whether Sinwar foresaw the consequences of the 7 October raid, as well as its primary objectives. It seems clear that he believed Hezbollah would launch a supporting offensive against Israel – which was a mistake – and may have believed that Israel would not attack Gaza with so many of its citizens held as hostages.
After the 7 October attack, Sinwar went into hiding, possibly in the network of tunnels Hamas have built under southern Gaza.