SAN DIEGO — What would have been the first court hearing about the deaths of 24 Iraqi civilians in Haditha has been delayed more than two months, an attorney said Wednesday.

Lt. Col. Jeffrey R. Chessani was due in a Camp Pendleton courtroom next week for a preliminary hearing, but the investigating officer can’t be there, attorney Brian Rooney said.

To accommodate the schedules of everyone involved, the next hearing was pushed back to May 30, he said.

Chessani is charged with dereliction of duty and violation of a lawful order. He is the highest ranking of eight Marines who were charged.

On Nov. 19, 2005, a Marine squad suffered one fatality when its convoy was rocked by a roadside bomb blast. In the aftermath of the explosion, troops killed 24 Iraqis.

Following several lengthy investigations, four enlisted Marines were charged in December with unpremeditated murder and four officers were charged with failing to adequately report the deaths.

Rooney said the charges were without merit and the defense team would use the delay to review nearly 5,000 pages of newly declassified evidence, which augments an already-bulky, 8,000-page investigation.

In the coming weeks, the attorneys plan to video record depositions by Chessani’s intelligence officer and executive officer before they are redeployed to Iraq, Rooney said. Lawyers also will review footage from a remotely operated aircraft that could show Marine reaction to the roadside bomb blast.

Rooney works for the Thomas More Law Center in Ann Arbor, Mich., a nonprofit Christian law firm that takes on issues of faith, family values and patriotism. Rooney said Chessani, from Rangely, Colo., is a committed Christian and the firm will represent him free of charge.

“He is a typical, no-nonsense, just-the-facts, this-is-what-happened career infantry officer,” Rooney said. “We are not hesitant to get into court.”

Rooney, a recently retired Marine captain, said he believes the actions of Chessani’s battalion were justifiable and Marines on the ground responded to the bomb blast with the right amount of force.

“I know of instances where Marines went into homes or hospitals or mosques and didn’t go in hard enough and ended up dead,” Rooney said.

An attorney for 1st Lt. Andrew A. Grayson, another officer charged in the case, said his client may have his pretrial hearing, known as an Article 32 investigation, on April 23. Hearings for other defendants are expected in the coming months, though the Marine Corps would not confirm any dates.