A military panel found that a Marine officer displayed substandard performance in his response to the deaths of 24 Iraqis but said he should maintain his rank.

The Board of Inquiry's recommendation is a mixed result for Lt. Col. Jeffrey Chessani, 43, who was accused of failing to investigate the November 2005 killings in the town of Haditha. Navy Secretary Ray Mabus must decide whether to accept the finding or order Chessani retired at a lesser rank.

Last year, a military judge dismissed a criminal charge of dereliction of duty against Chessani because of improper conduct involving two other people, the general overseeing the case and an investigator. Chessani was relieved of his command in 2006.

The panel comprised of a general and two colonels reached its decision Friday after a hearing at Camp Pendleton that lasted nearly two weeks. It found Chessani failed to provide as detailed and accurate report as he could have but that the shortcomings did not merit a reduction in rank.

"The only thing we're disappointed in is that we still don't believe, after all the evidence is in, that Col. Chessani was substandard in his performance," Brian Rooney, his civilian attorney, said Saturday.

The killings occurred after a roadside bomb killed a Marine and wounded two others, leading to the biggest criminal case against U.S. troops to come out of the Iraq war.

Chessani resisted an investigation after an initial inspection found no evidence of insurgent activity and Haditha leaders met with Marines to complain of war crimes, prosecutors said at the hearing. A full investigation did not begin until January 2006 when a Time magazine reporter inquired.

Defense attorneys said Chessani properly reported the deaths to his superiors. They portrayed him as a respected commander with 22 years of experience who was recommended for the Bronze Star, praised as a top battalion commander and singled out for advanced training and promotion.

"Everyone in that chain of command was aware that civilians were killed in residential structures," Lt. Col. Jon Shelburne, his military attorney, said in his opening statement.

Investigators said Marines shot five men by a car at the scene. The squad leader, Staff Sgt. Frank D. Wuterich, allegedly ordered men into several houses, where they cleared rooms with grenades and gunfire, killing more Iraqis, including women and children.

Eight Marines were charged with murder or with failing to properly report or investigate the killings. Charges were dismissed against six and one was acquitted. The sole remaining defendant is Wuterich, whose court-martial is not yet scheduled.