SAN DIEGO — A decorated Navy SEAL is facing charges of premeditated murder and numerous other offenses in connection with the fatal stabbing of a teenage Islamic State prisoner under his care in Iraq in 2017, along with the shooting of unarmed Iraqi civilians.

Special Operations Chief Edward Gallagher plans to plead not guilty to all the charges Friday during an arraignment hearing at Naval Base San Diego, his attorney Phil Stackhouse said.

The case stands out because of the seriousness of the allegations against an elite special warfare operator and the fact that the prosecution's case includes the accounts of fellow Navy SEALs, an extremely tight-knit group even by military standards.

Stackhouse said his client is being falsely accused by disgruntled SEALs who wanted to get rid of a demanding platoon leader.

Gallagher was awarded the Bronze Star twice.

Special Operations Chief Edward Gallagher via Facebook / @freeeddieg

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Navy prosecutors have painted a picture of a highly trained fighter and medic going off the rails on his eighth deployment — indiscriminately shooting at Iraqi civilians — and stabbing to death a captured Islamic State fighter estimated to be 15 years old, and then posing with the corpse at his re-enlistment ceremony.

If convicted, the 19-year Navy veteran faces life in prison.

At a two-day preliminary hearing at the Navy base in November, investigators said Gallagher stabbed the teen in the neck and body with a knife after he was handed over to the SEALs in the Iraqi city of Mosul to be treated for wounds sustained by the Iraqi Army and its prisoners during an airstrike in May 2017.

Naval Criminal Investigative Service Special Agent Joe Warpinski told the court that a SEAL medic told him he believed he had just stabilized the teen when Gallagher "walked up without saying anything at all" and started stabbing him. Afterward, prosecutors say he took photos of himself with the corpse, holding up his knife in one hand and the teen's head in the other. He also posed with the body during his re-enlistment ceremony captured in the footage, Warpinski said.

Warpinski said when another SEAL questioned Gallagher, the chief replied that "I was working on him, and he just died." His defense attorney also indicated to the court the teen died from injuries from the airstrike.

Warpinski, who spoke to nine members of SEAL Team 7, said he was told Gallagher would fire into crowds of Iraqis. He is accused of shooting an elderly man carting a water jug in Mosul in June 2017, and a month later shooting a girl walking along a riverbank in the same area. Investigators told the court that he had threatened to publicly name fellow SEALs if they reported his actions.

According to Warpinski, some SEALs were so concerned about his actions that they did not tell him his sniper rifle settings were off so his shooting would be less accurate and they would fire warning shots to clear areas of civilians.

There has been speculation that the case may widen to implicate others for not reporting what they witnessed. Prosecutors have already accused Gallagher's platoon commander, Navy Lt. Jacob Portier, of not acting on the allegations. His attorney Jeremiah Sullivan said Portier was the first to report them to superiors and did so as soon as he learned of them. His arraignment hearing has not been scheduled yet.

But Navy spokesman Brian O'rourke said the case for now is focusing solely on Gallagher and Portier. "There is zero interest in taking action against any witnesses at this time," O'rourke said.

Gallagher's attorney Stackhouse said his client looks forward to the trial to clear his name. "He's never run from a fight, and he's not going to run from this one," he said.

Stackhouse plans to ask the judge Friday to allow Gallagher to be released from the brig, where he has been held since his arrest Sept. 11.

The Navy SEALs Fund has raised more than $200,000 through an online fundraiser for his defense. According to the foundation's posting online: "Eddie's record and reputation as an elite warrior is rivaled only by a few men who have served by his side as special warfare operators and heroes who have gone before him."