What to Know Chief Special Warfare Operator Edward Gallagher is accused of premeditated murder after a stabbing in Mosul, Iraq in May 2017

Gallagher has served 19 years in the US Navy and was awarded the Bronze Star Medal twice

Prosecutors have said Gallagher tried to bribe fellow SEALs not to talk about the incident to NCIS investigators

A bombshell was dropped Thursday in the court-martial of a decorated U.S. Navy SEAL who was accused of murder in the death of an Islamic State fighter.

A prosecution witness testified he was the one who killed the fighter in Mosul, Iraq, in May 2017 — not Special Operations Chief Edward Gallagher, who faces charges of murder and attempted murder.

The witness, U.S. Navy SEAL SO1 Corey Scott, had wanted to invoke his Fifth Amendment right against self-incrimination, but the judge rejected that. Instead, he granted him immunity to testify for the prosecution.

Scott said he saw Gallagher stab the prisoner but in a way that would not have killed him: behind the collar bone toward the back on the right side.

“The stabbing I saw yes, he would have survived," Scott said.

For the first time, Scott said he was the one who killed the ISIS fighter by asphyxiation.

Scott testified that Gallagher did stab the ISIS fighter but was not the one who killed the teenager. Scott said he did that by putting his thumb over a breathing tube.

"I knew he was going to die anyway," Scott said. “I wanted to save him from waking up to what had happened next."

Scott said the fighter was going to be turned over to the Iraqi forces and that he had previously seen those forces torture, rape and murder prisoners.

The testimony rattled the prosecutor, who called his own witness a liar, according to NBC 7's Artie Ojeda, who was in the courtroom.

In previous interviews with investigators, Scott had said the fighter died of asphyxiation but no one asked him to clarify that.

Defense attorneys have said there’s no body, autopsy or forensic evidence to show a killing happened. The case was built on lies by junior SEALs who hated Gallagher because he was tough, according to the defense.

“The government will not be dropping premeditated murder charges against Chief Petty Officer Gallagher despite Petty Officer Scott’s testimony. The credibility of a witness is for the jury to decide.” Navy spokesperson Brian O'Rourke said.

Gallagher, whose case has drawn President Donald Trump’s attention, faces seven counts that include premeditated murder and attempted murder.

He’s also accused of shooting two civilians — an elderly man and a school-age girl — from sniper perches in Iraq in 2017.

He has pleaded not guilty and could face a life sentence.

On Wednesday, three Navy SEALs testified to the jury. The first of those, Navy Seal Dylan Dille, said Gallagher was his platoon chief when SEAL Team 7 was deployed to Mosul, Iraq.

Dille said that during a mission on May 3, 2017, there was an injured ISIS fighter in need of attention and he heard Chief Gallagher respond, “No one touch him, he’s all mine.”

Navy SEAL Craig Miller, who is now a chief, also testified Wednesday.

“I saw him stab the prisoner. I saw him stab him in the neck,” he told jurors.

Miller said he saw blood come from the right side of the fighter’s neck. The SEAL also said he told his commanding officer right after it happened.

The court was shown pictures of a re-enlistment ceremony, where the team was gathered around the dead body. Dille was not pictured, and Miller was pictured. Dille said he didn’t join the group photo because it was “unprofessional.”

He testified that Lt. Jacob “Jake” Portier, who is accused of covering up Gallagher’s war crimes, conducted the chief’s reenlistment ceremony.

The defense does not dispute that Gallagher posed with the corpse.

“Was the photo in poor taste? Probably,” Parlatore told jurors in his opening statement. “Was the photo evidence of murder? No.”

The trial is expected to last up to three weeks. The jury is composed of five enlisted men, including a Navy SEAL and four Marines, plus a Navy commander and a Marine chief warrant officer. Most of the jurors have served in conflicts in Iraq and Afghanistan.