ISIS's brutal leader was killed by US Delta Force soldiers. Here's how the elite raid on Baghdadi went down.

Syrian Democratic Forces (SDF) leader Mazloum Abdi has said that his forces began gathering intelligence on Baghdadi's whereabouts five months ago, according to The Washington Post.

In mid-2019, Reuters reports, Iraqi, US, and Turkish intelligence officials were able to nail down Idlib as the location of Baghdadi's hideout after capturing five senior ISIS leaders who told them locations where they were meeting Baghdadi.

Informants within Syria then found Ethawi at a market in Idlib and followed him to the house where Baghdadi was staying.

"We passed the details to the CIA and they used a satellite and drones to watch the location for the past five months," an Iraqi security official said.

Intelligence from former al-Qaeda affiliate Hayat Tahrir al-Sham (HTS), which controls the area surrounding Idlib, may have aided in Baghdadi's capture, too, Reuters reports.

A jihadi commander in Idlib said HTS had captured Abu Suleiman al-Khalidi, a close aide to Baghdadi. HTS is believed to work with Turkish forces in northwest Syria; information from Khalidi may have been passed on to other intelligence agencies.

Around the same time, The Washington Post reports, a disaffected ISIS member began to leak information to the SDF; as the US became more confident in the informant's credibility and put his intelligence together with additional information they had uncovered, the plot to capture or kill Baghdadi came together.

Vice President Mike Pence, speaking on CBS's "Face the Nation," said that US officials received intelligence about Baghdadi's whereabouts early last week, and on Thursday afternoon, officials "were informed that there was a high probability he would be at the compound in Idlib province."

On Friday, military officials provided Trump with different plans to go after Baghdadi, Pence said. That same day, according to Reuters, Baghdadi and his family left their compound by minibus, for the last time — perhaps the "actionable intelligence" Pence referenced which allowed US forces to embark on the Saturday operation.

Details are beginning to emerge about the secret operation that ended Baghdadi's life and horrific rule:

• The operation was code-named for Kayla Mueller, the American aid worker who was captured by ISIS and repeatedly raped by Baghdadi before she was killed. Mueller was abducted from Aleppo in 2013 and confirmed dead in 2015, although her body has not been recovered, CNN reports.
• Troops involved in the operation, including some members of the Army's Special Operations Delta Force, took off in eight helicopters out of Iraq early Sunday morning local time — Saturday afternoon East Coast time.
• The troops were met with small arms fire upon landing in Syria, about four miles from the Turkish border.
• The commandos involved in the operation called out to Baghdadi once they arrived at the compound to see if he would come out. They breached two walls of the compound with explosives, fearing the entrance was booby-trapped, after 11 children and a few adults emerged, according to The Washington Post.
• Baghdadi himself didn't emerge, instead retreating into the tunnels of the compound with three of his children. A dog working with US forces followed Baghdadi into the tunnel, where he detonated a suicide vest and killed himself and the children.
• US forces performed a DNA test on Baghdadi's remains in a secure location, Chairman of the Joint Chiefs of Staff Gen. Mark Milley said in a press conference Monday.
• The compound was destroyed by US firepower, including Hellfire missiles, Joint Air-to-Surface Standoff Missiles (JASSMs), and GBU laser-guided bombs, according to Milley.

Trump sat down in the situation room to watch the raid around 5:00 PM Eastern Time on Saturday, The New York Times reports.

Trump, Pence, Secretary of Defense Mark Esper, National Security Advisor Robert O'Brien, and other members of the national security team watched the raid unfold via overhead surveillance footage. No sound is available on such footage to prevent interference from the situation room during these operations, The New York Times reports.

While the troops involved in the raid were wearing body cameras, that footage was not relayed to the situation room in real time, as it contains disturbing images and can be disorienting. Instead, as The New York Times reports, that footage is intended to be viewed after the fact.

Trump described Baghdadi as "screaming, crying, and whimpering" when he died, although it's unclear how he obtained that information; he may have spoken to those directly involved.

The mission was complete and Baghdadi dead by 7:15 PM Eastern Time Saturday, National Security Advisor Robert O'Brien said on NBC's "Meet the Press" Sunday.

• The dog who followed Baghdadi into the tunnel was wounded in the operation but is recovering, although his name has not yet been released.
• It's unknown where, how, or if Baghdadi's remains were buried; Milley told reporters that the remains were disposed of "appropriately," and according to one report they were buried at sea. Navy SEALs buried al-Qaeda leader Osama bin Laden's remains at sea after the 2011 raid in Pakistan that killed him.
• Two men who were taken from the compound are in US custody, Milley told reporters during a press conference Monday afternoon.
• Abu Hassan al-Muhajir, a spokesman for ISIS and a likely successor to Baghdadi, was reported killed in Syria on Sunday in a separate operation, although US officials have not yet confirmed the operation, which is believed to have been a joint effort between US and SDF forces, The New York Times reports.