On Saturday night, Abu Bakr al-Baghdadi chose suicide over death or capture at the hands of the Delta operators of A Squadron. The operation, however, had begun months before the Delta shooters came in knocking at the leader of ISIS’ door.

The story behind the tracking of the leader of the Islamic State (ISIS) is as intriguing as the details of the Delta Force raid.

According to emerging reports, U.S. intelligence was able to pinpoint the location of the terrorist leader with the help of an informant, who was in al-Baghdadi’s close circle. The unnamed informant was an ISIS member and responsible for organizing and facilitating al-Baghdadi’s movement within Syria. He was also responsible for the construction of the compound where the terrorist leader was hiding. This knowledge would be key in the planning of the operation, since the Delta operators and Rangers now knew the layout of the structure and the existence of multiple tunnels–some of which were fakes in order to confuse any attackers.

Moreover, he was able to obtain one of al-Baghdadi’s underwear, which he smuggled and handed to his handlers. The DNA from the underwear helped ascertain that the leader of ISIS was indeed in the compound. He also informed his handlers that al-Baghdadi always traveled wearing a suicide vest in case he was concerned.

Most interesting of all, the informant was present during the operation. He was exfiltrated from the region two days after the raid alongside his family. He is expected to receive the $25 million bounty that was on al-Baghdadi’s head.

The informant–reports have him as a Sunni Arab–was nurtured by the Kurdish-led Syrian Democratic Forces (SDF), which would explain the statements of SDF officials that claimed credit for Operation Kayla Muller. The SDF operatives then passed the source to U.S. intelligence, which instigated its own rigorous vetting process.

The Chairman of the Joint Chiefs of Staff, Army General Mark Milley, refused to comment on the intelligence aspect of the operation stating that “I’m not going to comment on what may or may not have happened with the SDF on the objective. The actions on the objective, the aircraft coming in, the aircraft overhead and the soldiers conducting the assault, was a U.S.-only operation.”

The hunt for the leader of ISIS had intensified in the summer. American and French–Syria used to be a French colony–commandos scoured the area for al-Baghdadi. Regarding the American operators, they would most probably have come from the Intelligence Support Activity (ISA), a Special Mission Unit (SMU) specializing in Human Intelligence (HUMINT) and Signals Intelligence (SIGINT).

Despite all of the above information, U.S. intelligence was only able to assess al-Baghdadi’s location with confidence in September. And the major motivation behind launching the raid on October 26 was the concern that the terrorist leader was about to relocate to another safe house.

ISIS announced its new leader last week. In an eight-minute audio statement, the terrorist organization named Ibrahim al-Hashemi al-Qurayshi as the new caliph. And now, Al-Qurayshi has the dubious honor of being on the top of Delta’s target list.