CAMP PENDLETON - The highest-ranking officer accused of wrongdoing in the killing of 24 Iraqi civilians in the city of Haditha two years ago was arraigned in a Camp Pendleton courtroom Friday and is slated to go on trial in April.

Lt. Col. Jeffrey Chessani, 43, appeared before Col. Steven Folsom and said he would enter a plea at a later date to charges of willful dereliction of duty and violation of a lawful order.

Chessani said little during the brief session other than to identify himself and answer a few basic questions.

Afterward, one of his attorneys, Robert Muse, said at least two Marine Corps generals who were aware of the Haditha killings but did not order a formal investigation will be called to testify at the trial.

Muse said his client, who was relieved of his command of the 3rd Battalion, 1st Marine Regiment in the wake of the 2005 Haditha killings, is steadfast.

"He's unflappable," Muse said. "He's very focused on the case, and while it has been tiring and trying, he's a tough man."

Chessani's attorneys also reserved a decision on whether he will ask to be tried by a judge or by a jury of his peers. A jury could consist of six to 16 members and two-thirds of such a panel must agree in order to convict.

His attorneys have previously indicated that they would ask for a jury trial, but Muse said after this morning's hearing that Folsom is a well-respected chief judge and could be asked to decide the case alone.

The crux of the case against Chessani is that he failed to accurately report and investigate a possible violation of the laws of war by Marines under his command. The veteran of three Iraq deployments and holder of the Bronze Star medal faces up to 30 months in prison and a dismissal from the service if convicted.

During a hearing this summer that resulted in Chessani being ordered to court-martial, his attorneys sought to make it clear that their client wasn't the only senior Marine officer who didn't order an investigation into the Haditha killings.

One of those senior officers, Maj. Gen. Richard Huck, who had overall command of the Marine forces in Iraq at the time, testified that he relied on reporting that came up the chain, which said the civilian killings were "collateral damage" arising from combat.

The 24 Iraqis were killed by members of a Camp Pendleton unit after a roadside bomb destroyed a Humvee on the morning of Nov. 19, 2005, killing a lance corporal and injuring two other Marines. A search for the bomb triggerman and other insurgents led to the civilian deaths.

The incident did not become a criminal matter until a Time magazine reporter raised questions about what had taken place.

Those questions led to two investigations, one that probed the actions of Marine commanders in the wake of the killings and one that looked at the enlisted men responsible for the killings.

Last December, the Marine Corps filed dereliction of duty charges against four officers and murder charges against four enlisted men. In the time since, charges against two officers and two enlisted men have been dismissed.

Chessani is the highest-ranking officer to face criminal charges arising from a wartime action since the Vietnam war. Motion hearings in advance of his trial will take place in January, February and March.

Chessani's wife, Alissa, sat behind him during the court session. The couple is expecting their sixth child in December.

The Colorado native is being represented by a Christian-based Michigan firm, the Thomas More Law Center. In a written statement, center president Richard Thompson said Chessani is a victim of a malicious prosecution.

"Every patriotic American has a stake in the outcome of this case," Thompson wrote. "A U.S. Army colonel and an Army general conducted two separate investigations, and came to the same conclusion: There was no 'massacre' and no 'cover-up.' Yet the government still pursued a multimillion-dollar investigation in order to appease an antiwar politician and the 'blame America first' media.

"Now, we have the absurd situation of Lt. Col Chessani being charged with failing to report and investigate a crime that never occurred. Every American should be outraged at the way this dedicated Marine and his family are being treated by the nation he so loyally defended."

The Marine Corps has said it has spent at least $3 million prosecuting the Haditha case and the unrelated Hamdania case, in which eight other Camp Pendleton troops were convicted of offenses arising from the April 2006 abduction and slaying of an Iraqi man in the village of Hamdania.

Contact staff writer Mark Walker at (760) 740-3529 or mlwalker@nctimes.com.