In a testimony that could change the course of the war crimes trial of Navy SEAL Chief Edward “Eddie” Gallagher, a medic told jurors on Thursday, June 20, that he, and not Gallagher, was responsible for the 2017 death of a teen ISIS fighter after he had been brought to a compound with injuries suffered during an airstrike in a nearby village.

Navy SEAL Corey Scott, a special warfare operator who was testifying for the prosecution on a grant of immunity, said Thursday that Gallagher plunged a knife into the neck of the teen but did not actually kill him. On Wednesday, Navy Special Warfare Operator Craig Miller also testified that he was an eyewitness to the stabbing.

Scott, who served with Gallagher on SEAL Team 7, said Thursday that the stabbing by Gallagher wasn’t fatal and that after Gallagher walked away, Scott held the teen’s head and put his thumb over the breathing tube until the teen asphyxiated, as an “act of mercy.”

Scott’s testimony came on the third day of the court proceeding held at Naval Base San Diego.

Gallagher, a special warfare operations chief, is accused in the premeditated murder of the 15-year-old ISIS fighter, along with committing other war crimes during his deployment to Iraq. Gallagher, who has two bronze stars and has served on eight deployments, has pleaded “not guilty” to all charges in the high-profile case that has taken twists and turns since Sept. 11, 2018, when he was arrested at Camp Pendleton’s Intrepid Spirit Center, where he was undergoing a medical screening.

On Thursday, Scott testified that prior to the stabbing, the teen had been stabilized and was breathing normally after he and Gallagher treated the wounds.

Tim Parlatore, the lead defense attorney, then asked Scott: “Did Chief Gallagher kill this terrorist?”

Scott answered, “No.”

Following Scott’s testimony, the prosecution treated him as a hostile witness and accused him of lying to protect Gallagher from going to jail.

“He’s got a wife and family,” Scott said. “I don’t think he should spend the rest of his life in prison.”

Scott added that the ISIS fighter would have survived the stabbing, but he chose to plug the air tube because he believed the boy eventually would be tortured by Iraqi forces.

Thursday’s testimony drew praise from Andrea Gallagher, the defendant’s wife, who on social media credited Parlatore and the defense team with a “big day for our team!”

Following Thursday’s court proceedings, Parlatore reiterated that the best defense for Gallagher is the truth.

“Today, the truth started to come out,” Parlatore said. “What we’ve been saying for all this time, this is a shoddy investigation. No investigator, no prosecutor ever asked the question of what is the cause of death. They didn’t even go and hire a forensic pathologist until after they had charged him and threw him in jail. Today for the first time, someone asked the real question: ‘What is the cause of death?’ What we learned is that Chief Gallagher is not guilty of murder. The trial is certainly going to continue, but I expect at the end of this there will be a “not guilty” verdict.”

Gallagher, 40, is also accused of posing with the ISIS fighter’s body for a photograph while he and other SEALs held a reenlistment ceremony. He faces seven counts that include premeditated murder and attempted murder. He also is accused of shooting two civilians from sniper perches in Iraq in 2017.

The Associated Press contributed to this report.