The commander of the Marine battalion accused of killing 24 Iraqi civilians, including children in their pajamas, in Haditha went before a military court Wednesday to determine if he would stand trial for his alleged role in the biggest U.S. criminal case involving civilian deaths in the Iraq war.

Lt. Col. Jeffrey R. Chessani is the highest-ranking Marine charged in the deadly sweep of the village after a roadside bomb killed one Marine and injured two others.

The Article 32 investigation — the military equivalent to a civilian grand jury — will determine whether he stands trial on charges of dereliction of duty and violating a lawful order for failing to investigate the deaths of the men, women and children. If convicted, he faces up to three years in prison.

Marine lawyers began the hearing with hours of videotaped testimony from Marines who are now on duty in Iraq. The proceeding could last a week.

The case is one of several, including the Abu Ghraib prison abuse scandal and a rape slaying of a teenage girl and the murder of her family, that have further stoked Iraqi resentment over the U.S.'s continued presence in the war-ravaged country.

Chessani, 43, had inspected the scene after the Nov. 19, 2005, killings and "saw no law-of-war violation," said his attorney Brian Rooney. He said Chessani immediately reported the facts as he understood them to his boss, the commanding officer for the 2nd Marine Regiment.

"That same night, he knew exactly what Chessani knew," Rooney said. "My guy is not guilty, and neither are these other guys."

During several days of testimony earlier this month for Capt. Randy W. Stone, also charged in the case, a two-star general said he knew about the deaths but saw no need to investigate because he believed they happened during a legitimate combat operation.

The Haditha civilians were killed shortly after a roadside bomb killed a Marine and injured two others nearby. In the aftermath of the blast, a Marine squad went house to house looking for those responsible.

The Marines have said they believed they were taking fire from the houses. They used fragmentation grenades and machine guns to clear the homes, but instead of hitting insurgents, they killed civilians.

Three other officers are also charged with dereliction of duty, and three enlisted Marines are charged with murder. All belonged to the Camp Pendleton-based 3rd Battalion, 1st Marine Regiment.

Rooney said he wanted several high-ranking officers to testify at the hearing.

One witnesses he wants to call, Maj. Gen. Stephen T. Johnson, was the commanding general of Marines in western Iraq when the killings took place. Johnson told investigators he did not feel the slayings were significant.

"Examples of many civilians being killed at a time were precedent for that," Johnson told investigators. "It happened all the time."

Johnson is unlikely to testify; Rooney said he has asserted his constitutional privileges against self-incrimination.

Rooney works for the Thomas More Law Center in Ann Arbor, Michigan, a nonprofit Christian law firm that takes on issues of faith, family values and patriotism. Rooney said Chessani, from Rangely, Colorado, will be represented free of charge.

During Stone's recent hearing, Sgt. Maj. Edward Sax testified that "Chessani is the most morally correct Marine officer I have ever served with in my 27 years I have served."

Maj. Samuel Carrasco testified that Chessani shouted, "My men are not murderers," after learning of allegations that his troops targeted civilians.

Chessani "apologized for his outburst" and said the slayings would be reviewed, Carrasco said, adding "he had an incredible amount of agitation, frustration."