With everyone praising Delta Force and the rest of the assault force for the killing of the leader of ISIS, it’s worth taking a moment and reflecting the operations and sacrifices that have led to this moment.

Delta has led the campaign against ISIS since 2015, either by conducting surgical raids or unconventional warfare in partnership with the Kurds.

The following helmet camera footage shows the hostage rescue operation that Delta Force and its Kurdish SOF partners conducted on October 22, 2015. The joint assault force rescued approximately 70 hostages who were facing imminent execution by their ISIS captors. The prison was located near the town of Hawija, Iraq.

The footage shows the later phases of the operation, where the assault force subdues the last remnants of enemy fighters, shepherds the hostages, and begins the critical Sensitive Site Exploitation (SSE) process.

In the initial phase of the mission, Delta shooter Master Sergeant Joshua Wheeler was killed as he led the way into the heavily defended building. He became the first of two casualties Delta has suffered in its campaign against ISIS. Master Sergeant John Dunbar is the second.

A number of Joint Special Operations Command (JSOC) sources with intimate knowledge of the operation spoke to SOFREP about that fateful night.  What they described is a story of leadership and bravery under fire.

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Intelligence indicated that the prisoners were facing imminent execution after freshly dug mass graves were spotted in the compound’s perimeter.  Discovering this, the Kurds were adamant to go in even without American forces (the U.S. didn’t have a real stake in assaulting the compound). They thus took the mission lead. The plan that the Kurds came up with, however, was below average and would have resulted in a catastrophe if it hadn’t been for the tactful recommendations of their Delta partners.

The Unit agreed to accompany the Kurd assault force, and the 160th Special Operations Aviation Regiment (160th SOAR) chipped in the air transport. But once on target, the Delta operators were supposed to stay back and let the Kurds breach and clear the target. The compound was surrounded by a wall. Behind the wall, there were a number of buildings. One of those buildings contained the hostages.

Once on target, the assault force was divided in to two parts: The Kurds took the lead and assaulted the compound while the Delta operators stayed behind and provided support. The Kurds breached the wall and flooded into the compound. Identifying the correct building, they ran toward it and breached it. At that moment, however, they began receiving accurate fire from the other structures, which were occupied by ISIS fighters. The Kurds began suffering casualties, and the attack lost momentum at the most critical point.

The Delta operators could see and hear everything from their vantage point. And they understood that if they didn’t do something then the Kurdish assault would turn in to a bloodbath.  The imposing figure of MSG Wheeler was in the front of the Delta group. He turned around, locked eyes with the nearest operator, and shouted: “On me!”

These were his last words.

The two shooters ran through the wall, into the compound, and past the pinned down Kurds. MSG Wheeler led the way into the target building. As he stormed into the breach, a random bullet went through his throat. He died almost instantaneously. His fellow operator neutralized the enemy fighters in the room. The rest of the Delta shooters came in and cleared the rest of the building.

“This would have been a disaster hadn’t Wheels been there,” said one Delta operator.

According to his brothers-in-arms, MSG Wheeler, known to them as “Wheels,” was an outgoing country chap. Even in a unit such as Delta, Wheels’ tactical genius made him stand out. This was the last mission of his last combat rotation. He was set to retire when the Squadron rotated back to the States.

Ashton Carter, the Secretary of Defense at the time, had said in a statement that MSG Wheeler “ran to the sound of the guns, and he stood up, and all the indications are it was his actions and that of one of his teammates that protected those who were involved in breaching the compound and made the mission successful.”

Despite al-Baghdadi’s death, it’s important to highlight that the fight against the terrorist group hasn’t ended. Even as you read these words, Delta and the rest of the U.S. forces deployed in the region continue the destruction of ISIS.