“Last night, the United States brought the world’s No. 1 terrorist leader to justice,” the president said in a national address from the White House.

Mr. al-Baghdadi was chased to the end of a tunnel “whimpering and crying and screaming all the way” as he was pursued by U.S. forces, said Mr. Trump. Mr. al-Baghdadi, who had three of his children with him, then detonated a suicide vest, killing himself and the children, Mr. Trump said.

Details: The C.I.A. was tipped off to Mr. al-Baghdadi’s location following the arrest and interrogation of one of his wives and a courier this summer. The agency then worked closely with Iraqi and Kurdish intelligence officials to monitor his movements.

But Mr. Trump’s abrupt decision to withdraw American forces from northern Syria disrupted the meticulous planning and forced Pentagon officials to press ahead with a risky night raid.

Go deeper: Our ISIS correspondent, Rukmini Callimachi, started interviewing people who had interacted with Mr. al-Baghdadi in 2015, to create a portrait of the leader of the deadly terrorist organization.