TEL AVIV — Where is Yahya Sinwar? As the four-month anniversary of the Oct. 7 terrorist attack on Israel approaches, the elusive Hamas leader believed to be the architect of the assault has managed to stay one step ahead of Israel’s military and intelligence services.

Israel Defense Forces recently found cages where they say hostages were kept deep under Khan Younis, Sinwar’s birthplace and a densely populated hub for Hamas’ political activity, current and former Israeli officials told NBC News. They say Sinwar and other Hamas leaders have likely been hiding nearby, carefully protected by layers of Israeli captives and lower-tier Hamas fighters.

“It is a fair assumption that Sinwar and Hamas leadership were close to where those hostages were kept — and then they all moved on,” said Jonathan Conricus, a lieutenant colonel in the Israeli reserves and former IDF spokesman who is now a senior fellow at the Foundation for Defense of Democracies, a Washington-based policy institute. “I think being close to hostages has saved his life more than once.”

Hamas has also taken great pains to keep Sinwar’s communications with its political leaders in Doha, the capital of Qatar, undetected by Israeli intelligence, current and former IDF officials said, including during the cease-fire in November that led to the release of around 100 hostages.

A Hamas political official told NBC News that the organization is trying to protect Sinwar and its other top leaders. “I think that this is the right of any leadership or any resistance,” said the official, who asked not to be named. “I am sure that is the same in every country.”

Sinwar is believed to have planned and overseen the surprise attack, which killed 1,200 people in Israel and led to the kidnapping of 240 people from multiple countries, according to Israeli officials. It was the deadliest day in the country’s 75-year history.

Since Israel began bombing Gaza in retaliation, more than 25,700 Palestinians have died, according to health officials there. Thousands more are missing and presumed dead.

Sinwar has likely stayed on the move, changing locations to avoid detection, according to military commanders, current and former security officials and experts who have liaised with Hamas in the past.

This week, Israeli forces surrounded Khan Younis, the largest city in southern Gaza. They believe Sinwar is deep in a maze of tunnels somewhere below Gaza, but they cannot rule out the possibility that he may have crossed into Egypt through a tunnel.

Israel has floated an offer to allow for the safe passage of Sinwar and other Hamas leaders out of Gaza in exchange for the release of all the remaining hostages. Negotiations are ongoing but no such deal is imminent, according to sources familiar with the talks.

A former Israeli official who has extensive experience negotiating with Palestinians expressed concerns about such an outcome. “If he lives abroad and supervises the remaining leaders of Hamas in Gaza and Hamas gets a role in a future arrangement in Gaza, well that amplifies his victory on Oct 7,” the official said.

Two other former Israeli officials said Sinwar has three interests: his own survival, Hamas’ organizational continuity, and a role in the future leadership of Gaza. “They did Oct. 7 as a step toward their goal,” said a former Israeli official who believes that Sinwar hopes to survive.

The Israeli hunt for Sinwar is playing out as multiple countries, including the U.S., Qatar and Egypt, engage in high-stakes talks aimed at finding an off-ramp for the conflict. Hamas has demanded that Israel permanently halt its offensive before any hostages are released, a demand Israeli Prime Minister Benjamin Netanyahu has rejected and said would endanger Israelis.

Jacob Nagel, who served as Netanyahu’s national security adviser from 2016-2017, predicted that Sinwar will never give up all of his captives. “He’ll keep some of the hostages forever because this will be his insurance policy that no one will kill him,” said Nagel, who is also a senior fellow at the Foundation for Defense of Democracies.

Israeli leaders across the country’s political spectrum agree that the war on Hamas must continue and the dismantling of the terror group must be achieved. But there is momentum behind the idea that Israel should first get the hostages out and then take the time it needs to defeat Hamas.

Gershon Baskin, an Israeli who has acted as a mediator with Hamas for decades, does not believe that Sinwar will agree to a deal that involves him leaving Gaza to live in a regional safe haven such as Doha or Beirut. 

“I do not believe this is going to happen,” said Baskin. “This is not Yasser Arafat in 1982 escaping to Beirut with the Palestinian Liberation Organization. This is a totally different mindset.”

Baskin says Sinwar will go down fighting because in his world view, his fastest way to paradise is to die after killing as many Jews as possible.

“I believe Sinwar knows he will die a martyr and he’s not afraid of death,” Baskin added. “This is Hamas’s distorted version of Islam. Life on earth is short and paradise is eternal.”

When the IDF pulled out of the Gaza Strip in 2005, current and former Israeli officials say, their intelligence began to decline in the densely populated enclave. The following year, Hamas won the Palestinian legislative election in Gaza by campaigning on armed resistance against what the group calls the Israeli occupation. 

“They don’t have the same intelligence in Gaza as they do in the West Bank,” said Baskin. “In the West Bank, they have every house mapped out, they know who lives in each house, and when there are terrorist attacks and people in the West Bank escape, the IDF can find them.”

Sinwar joined Hamas after it was founded in 1987. In 1989, he was imprisoned in Israel for plotting to kill two Israeli soldiers and admitting to killing a group of Palestinians he believed were collaborating. He served 22 years of a life sentence when he was released in 2011 as part of a deal Netanyahu made to free 1,027 Palestinian prisoners in exchange for Gilad Shalit, an Israeli soldier who Hamas held captive in Gaza for five years.

“When Israel was not in Gaza, Gilad Shalit was in captivity for five years, which is remarkable,” said Baskin, who negotiated with Sinwar through an intermediary to secure Shalit’s release. 

The intense hunt for Sinwar is taking place in tandem with a search for the more than 130 hostages who are still being held captive, some of whom Israeli intelligence believes are already dead.

Pictures of the hostages are ubiquitous inside the halls of the Knesset in Jerusalem, a reminder of the stakes for Israeli leaders. Baskin predicted that Sinwar’s days are numbered.

“In his own delusional view of the world, Sinwar thinks he will emerge from the tunnel victorious,” Baskin said, “but inevitably Israel is going to find him.”