“The guy is freaking evil,” Special Operator Miller told investigators. “The guy was toxic,” Special Operator First Class Joshua Vriens, a sniper, said in a separate interview. “You could tell he was perfectly O.K. with killing anybody that was moving,” Special Operator First Class Corey Scott, a medic in the platoon, told the investigators.

In the interviews, platoon members said they saw Chief Gallagher shoot civilians and fatally stab a wounded captive with a hunting knife.

Three SEALs said they saw Chief Gallagher go on to stab the sedated captive for no reason, and then hold an impromptu re-enlistment ceremony over the body, as if it were a trophy.

“I was listening to it, and I was just thinking, like, this is the most disgraceful thing I’ve ever seen in my life,” Special Operator Miller, who has since been promoted to chief, told investigators.

Some of the SEALs said they came to believe that the chief was purposefully exposing them to enemy fire to bait ISIS fighters into revealing their positions. They said the chief thought that casualties in the platoon would increase his chances for a Silver Star.