Opening arguments are set to begin on Tuesday in the trial of a U.S. navy SEAL court-martialled on charges of murdering a wounded Iraqi prisoner and shooting unarmed civilians, a war crimes case that has drawn the attention of U.S. President Donald Trump.

A jury was selected on Monday in the trial of Special Operations Chief Edward Gallagher, City News Service and the Fox affiliate in San Diego reported.

Gallagher, a 39-year-old career combat veteran, has denied all the charges but could face life in prison if convicted in the trial arising from his 2017 deployment to Mosul, Iraq.

The platoon leader is charged with murdering a wounded, helpless Islamic State in Iraq and Syria (ISIS) fighter in his custody by stabbing him in the neck, and with attempted murder in the wounding of two civilians — a schoolgirl and an elderly man — shot from a sniper’s perch in Iraq.

He maintains that fellow SEAL team members in his platoon, who turned him in and are testifying against him under grants of immunity, are disgruntled subordinates who fabricated allegations to force him from command.

Details of the jury were not immediately available. A navy spokesperson said on Monday between five and 15 jurors would be selected from a pool, half of whom are officers and the other half enlisted men.

The proceedings in a military courthouse at U.S. Naval Base San Diego are due to last three weeks.

The prosecution’s case rests crucially on the SEAL team members’ testimony as there are no bodies or crime scenes from the Iraqi war zone. Names and other details about the alleged crimes were not disclosed.

Prosecutorial misconduct alleged

The opening of the trial was postponed several times by a lengthy round of proceedings to deal with defence allegations of prosecutorial misconduct.

Gallagher’s lawyers sought dismissal of the charges after learning that navy prosecutors had electronically tracked email communications of defence lawyers without a warrant, ostensibly to pinpoint the source of material leaked from sealed case files.

The presiding judge, a navy captain, ultimately removed the lead prosecutor from the case and freed Gallagher from pre-trial confinement.

The judge also granted defence lawyers a potentially valuable edge in jury selection – the right to reject, with no reason given, two more potential jurors than they otherwise could exclude through the use of a peremptory challenge.

Former U.S. army member King Cohn arrives at court to support U.S. navy SEAL member Edward Gallagher on Monday in San Diego. (Mike Blake/Reuters)

Before he was released from custody late last month, Gallagher had been ordered restricted to base at the nearby Naval Medical Center San Diego.

The confinement itself had already been the subject of news stories on conservative media outlets. Trump, responding to a Fox and Friends segment on Fox News, tweeted on March 30: “In honor of his past service to our Country, Navy Seal #EddieGallagher will soon be moved to less restrictive confinement while he awaits his day in court.”

Trump said last month that he is considering pardons for a number of military service members accused of war crimes, and Gallagher’s case was believed to be one of those under review. Last month, he pardoned Army veteran Michael Behenna, who was convicted of murdering an Iraqi prisoner in 2009.

The prospect of presidential clemency seemed heightened by last month’s appointment to Gallagher’s defence team of Marc Mukasey, one of Trump’s personal lawyers.

Ted Lieu, Democratic California congressman and Air Force veteran who helped prosecute cases in the military, expressed alarm that Trump was even speculating about the case before it had been adjudicated.

“The charges against Gallagher are deadly serious,” Lieu said on Twitter on May 18. “[The president] should not circumvent the court-martial process. Let military jurors decide.”

Gallagher’s lead civilian attorney, Timothy Parlatore, has said his client has not sought a pardon.

As well, at least two Republican congressmen have also spoken out in support Gallagher.

Dan Crenshaw of Texas, a former navy SEAL, had expressed concerns about Gallagher’s detention before he was released, while Duncan Hunter from California expressed doubts Gallagher could get a fair trial in the wake of the allegations about the prosecution.

Hunter, a former marine who served in Iraq, raised controversy when he told a town hall in late May that like Gallagher, he too had posed for a picture alongside a corpse while serving.

“Eddie did one bad thing that I’m guilty of, too — taking a picture of the body and saying something stupid,” said Hunter.