After years of appeals and delays, the last US Marine charged over the 2005 killings of 24 civilians in the Iraqi town of Haditha faces a court martial on Thursday in California.

United States troops may have left Iraq, but there is still unfinished business in the legal arena with one of the most controversial criminal cases involving the US military during the nearly nine-year-long Iraq war.

Staff Sergeant Frank Wuterich, 31, faces nine counts of voluntary manslaughter and other charges for his role in the November 19, 2005 deaths of 24 Iraqi civilians, many of them women and children.

"He's going to be glad to have it over, because he knows that he'll be exonerated," Wuterich's lawyer Neal Puckett told National Public Radio (NPR) ahead of the military trial at Camp Pendleton, California.

"The world will know (that) the truth about what happened at Haditha can't be attributed to his criminal behavior, and he just needs to move on with his life," he added.

Wuterich, who had no previous combat experience, was the squad leader who sent his men into a village to hunt for insurgents following a roadside bombing that killed a fellow Marine and injured two other Marines.

Nineteen people were killed inside houses, along with five men who pulled up near the bombing scene in a car.

The Marines said after the violence in Haditha that 15 Iraqis had been killed by the roadside bomb that killed the Marine.

But a subsequent investigation by Time magazine showed most of the dead were killed as Marines swept through three houses near the site of the bombing.

Lawyers for the Marines said insurgents hid behind civilian homes and opened fire, sparking a shootout that would fall within legal rules of engagement.

But the plaintiffs said there were no such insurgents and that the Marines initiated a bloody three-hour rampage to avenge the death of their comrade.

Among the victims, 10 were women or children, killed at point-blank range.

Wuterich's attorneys have exhausted all possible appeals on behalf of their client, including an attempt to dismiss charges based on the forced retirement of one of the military defense attorneys.

Another ruling against the defense team allowed military prosecutors access to unaired portions of the CBS "60 Minutes" interview of Wuterich, which was conducted prior to charges being filed.

Wuterich remains on active duty at Camp Pendleton while awaiting resolution of his case.

If convicted of all charges, he could be sentenced to life in prison, but military juries in Iraq-related Camp Pendleton trials have been reluctant to convict their peers or have recommended very light sentences.

Wuterich has asked for his jury to include some enlisted personnel, and recent trials have included many Iraq and Afghanistan combat veterans.

The other seven Marines charged in the case have been exonerated through various legal rulings.

Pre-trial motions were heard on Wednesday. Jury selection begins at 8:00 am (1500 GMT) Thursday, followed possibly by opening statements, if time allows. The trial is expected to last about a month.

Wuterich has some heavy hitters defending him at the military trial in California: former military attorneys Puckett and Haytham Faraj.

Prosecutors in the case are Lt. Col. Sean Sullivan and Major Nicholas Gannon, who have prosecuted many other Iraq-related cases at Camp Pendleton, which lies just up the California coast from San Diego.