Who was Yahya Sinwar? Israeli military says it killed Hamas leader responsible for Oct. 7 attacks

The Israeli military claims it killed top Hamas leader Yahya Sinwar in the southern Gaza Strip Wednesday night.

Sinwar has been credited with being the mastermind behind the Oct. 7, 2023, Hamas attacks, during which over 1,100 people were killed and 250 were taken hostage. It was the deadliest attack against Jewish people since the Holocaust.

Israel Defense Forces said in an X post on Oct. 17 that they were investigating whether Sinwar was one of the three terrorists killed during a patrol in Gaza. The Associated Press reported that Israel was using Sinwar's DNA, which is on file from his time in prison, to determine whether he was one of the terrorists killed. IDF stressed there were no hostages in the area.

Hours later, the IDF posted that they had "eliminated" Sinwar.

Sinwar's death is the most significant assassination of a Hamas official since Mohammed Deif, the group's military leader, and Ismail Haniyeh, Hamas's political leader, were both killed in July.

Who was Yahya Sinwar?

Sinwar, 61, had been involved with Hamas since joining the group in the early 1980s and took over as the head of the political bureau within the organization in July after former leader Haniyeh was assassinated in Iran.

Sinwar and Deif are believed to be the architects behind the Oct. 7 attacks. Both Sinwar and Deif had been designated as global terrorists by the U.S. State Department since 2015.

As of reporting in August, Sinwar has not been seen publicly since the attacks. In December, Israeli Prime Minister Benjamin Netanyahu said the IDF had surrounded Sinwar's home, but it was discovered that Sinwar was hiding in the network of tunnels beneath Rafah in southern Gaza. Israel reported they killed Deif in an airstrike in July.

"He chose to send the butchers into our bedrooms to kill our babies," Lt. Col. Peter Lerner, a spokesman for the Israeli military, told NBC News of Sinwar in 2023. "And when they chose to go full front against Israel, they signed their own death warrant. A dead man walking. We will get to that man."

What does Sinwar’s death mean for the Israel-Hamas war?

Since Sinwar was considered Israel's top target, his death would be, as Reuters reports, "a major boost to the Israeli military and Prime Minister Benjamin Netanyahu."

The New York Times reported in early October that Sinwar was blocking ceasefire and hostage exchange deals and U.S. negotiators thought he, and therefore Hamas, had no intention of reaching a deal with Israel.

In September, Danny Danon, Israel's ambassador to the United Nations, told France 24 that Israel was "determined" to capture or kill Sinwar and that the nation has "no intention to stay in Gaza" after that is accomplished.