ISTANBUL – Fluttering down from the skies over the Gaza Strip on a recent day were clouds of flyers dropped by the Israeli military asking for tips on the whereabouts of top Hamas leaders.

“The end of Hamas is near,” the flyers proclaimed in Arabic, promising hefty bounties to anyone who helped bring about the arrest of those who had “brought destruction and ruin to the Gaza Strip”.

The Hamas leader in Gaza Yehia Sinwar headed the list in exchange for a reward of US$400,000 (S$532,000) – more than 1,500 times Gaza’s average monthly wage.

Israel’s stated goal in the war is to destroy Hamas, the armed Palestinian group that rules Gaza and set off the war there by attacking Israel on Oct 7.

But despite a military campaign that has caused nearly 20,000 deaths in Gaza and reduced entire neighbourhoods to rubble, Israel has yet to locate Sinwar and other senior Hamas figures considered key plotters of the attack 10 weeks ago.

Israel considers Sinwar central to the Oct 7 attack, which killed roughly 1,200 people, with some 240 others taken back to Gaza as captives, Israeli officials say.

Now in his 50s, he was a founding member of Hamas in the late 1980s and developed a harsh reputation for punishing Palestinians suspected of spying for Israel.

“He is a very tough guy, a brutal guy,” said Associate Professor Mkhaimar Abusada, a political science expert at Al-Azhar University in Gaza who is now in Cairo.

Sinwar’s die-hard commitment to his organisation’s Islamist ideology makes it unlikely he will go down easily.

“If he is killed, he is going to go to heaven. He doesn’t really care much about his life,” Assoc Prof Abusada said, describing Sinwar’s mentality. “Israel would be mistaken if it thought that he was going to surrender or that Sinwar was going to raise a white flag.”

Israel is also seeking Sinwar’s brother and confidant, Mohammed. He has not been seen since the war began, although the Israeli military this week released a Hamas video captured in Gaza it said showed him riding in a car through an underground tunnel in Gaza.

The flyers dropped over Gaza offered US$300,000 for information leading to his capture.

Also named in the flyers were Rafi Salameh, a Hamas military commander, and Mohammed Deif, the leader of the Hamas armed wing, the Qassam Brigades, who is believed to have lost an eye and been seriously wounded in previous Israeli attempts to assassinate him.

Israel offered US$200,000 for information about Salameh and US$100,000 for Deif.

But the greatest symbolic and operational blow Israel could deal to Hamas would be to kill Yehia Sinwar, analysts and Israeli officials said.

Despite the destruction of much of Hamas’ infrastructure in Gaza, Sinwar still has some control over the group’s operations and was able to deliver on swaps of captives with Israel in November that had been negotiated by Hamas leaders in exile.

Unlike most Hamas military figures, who remained in the shadows even before this war began, Sinwar often attended events and gave speeches, which raised his profile among Palestinians and Israelis.

His killing would not only challenge Hamas operations but almost certainly dampen morale, while cheering Israelis.

The elusiveness of these top Hamas figures is depriving Prime Minister Benjamin Netanyahu’s government of tangible proof to show both his domestic audience and a growing chorus of foreign leaders calling for a ceasefire that Israel is progressing toward its goal of wiping out Hamas.

In the last 10 days, about two-thirds of the United Nations General Assembly approved a non-binding resolution calling for an immediate ceasefire; Britain, France and Germany urged a truce; and the Biden administration dispatched senior officials to press Israel to scale back the intensity of the war in the coming weeks in favour of a tactical campaign focused on Hamas.

But Mr Netanyahu has vowed to keep fighting, and Israeli officials have suggested a longer timeline that could see intensive bombing and ground manoeuvres well into 2024.

Israeli officials insist that they have made progress in degrading Hamas by killing thousands of its fighters, including important commanders, and destroying parts of a vast tunnel network the group built to secretly shuttle fighters and weapons around the territory.

The fact that the most senior Hamas leaders in Gaza have so far bedevilled Israel’s attempts to find them leaves open the possibility that they could survive the war and work to revive the group’s capabilities after the guns fall silent.

Israel had already missed several opportunities over the years to remove Sinwar from the battlefield.

He was arrested in 1988 and put on trial for the murders of four Palestinians suspected of spying for Israel, according to Israeli court records.

He spent more than two decades in prison in Israel, where he later said he passed his time getting to know his enemy: He learned Hebrew, read widely and became a leader among Palestinian prisoners.

“There is no doubt that he is stubborn and a good negotiator,” said Mr Sofyan Abu Zaydeh, a former Palestinian official in the West Bank who met Sinwar near the end of his own 12-year prison stint in the late 1980s.

He described Sinwar as deeply ideological. In 1993, other Palestinian factions signed interim peace agreements with Israel known as the Oslo Accords, recognising Israel’s right to exist and creating the Palestinian Authority, a sort of government-in-waiting.

Hamas rejected those agreements, sticking to its commitment to destroying Israel, and Sinwar refused to meet representatives of the more moderate Palestinian Authority.

“He said that those who are products of Oslo, I don’t recognise them,” Mr Abu Zaydeh said.

Sinwar was serving multiple life sentences, but in 2011 he was released in a swap of 1,026 Palestinians for one Israeli soldier, Gilad Shalit, captured by Hamas five years earlier.

Mr Yuval Bitton, a former head of the Israeli Prison Services Intelligence Division, said Israel had decided to release Sinwar instead of other prisoners because he did not have Israeli blood on his hands.

Exchanging Palestinian prisoners who have killed Israelis is a highly charged issue for the Israeli public and rarely happens.

Mr Bitton, who was in the service at the time but not yet its head, said he had seen Sinwar’s ability to affect other prisoners and even events outside the prison and so had argued against Sinwar’s release.

“I told them that the fact that he would be released would influence the field very, very much – that he was a great danger and that within a year he would be the head of Hamas.”

He was overruled.

Six years later, in 2017, Sinwar became the head of Hamas in Gaza. He gave fiery speeches calling on Palestinians to prepare rifles, cleavers, axes and knives to fight Israel, and had a flair for the dramatic.

Sinwar’s location remains a mystery, as are his thoughts about the war and the future of Hamas. But people who have met him said that any hope he would surrender to stop the war was in vain, regardless of what that meant for Gaza’s civilians.

“He is going to fight until the end of it,” said Assoc Prof Abusada. “Unfortunately, the more this goes on, the more the Palestinian civilian population loses.” NYTIMES