Attorneys asked a military judge Wednesday to dismiss charges against a Marine Corps officer accused of failing to investigate the killing of 24 people by Marines in Haditha, Iraq. The attorneys from the Thomas More Law Center filed five motions in advance of a pretrial hearing for Lt. Col. Jeffrey R. Chessani. He is the highest-ranking U.S. serviceman to face a combat-related court-martial since the Vietnam War. Chessani was charged with dereliction of duty and violation of a lawful order on allegations that he mishandled the aftermath of the Nov. 19, 2005, shooting deaths.

Among the motions the judge was expected to consider during the two-day hearing were requests to compel the deposition of Rep. John Murtha over comments the congressman made about Marines killing "in cold blood" in Haditha, and motions to dismiss charges because of undue influence by commanding officers.

On the day of the shootings, a convoy was struck by a roadside bomb, killing one Marine and wounding another. In the aftermath, members of one squad killed 24 Iraqi civilians, authorities allege.

Chessani has said he never ordered a formal investigation because he believed the deaths resulted from lawful combat.

Chessani, of Rangely, Colo., faces court-martial on April 28. If convicted on all counts, he faces up to three years in prison.

Four enlisted Marines were initially charged with murder in the case, and four officers were charged with failing to investigate the deaths. Charges against several of the men have been dropped, and none will face murder charges.

In a neighboring courtroom, a three-day pre-trial hearing was under way Wednesday or the squad leader, Staff Sgt. Frank Wuterich, 27, of Meriden, Conn., who faces charges including voluntary manslaughter.

Wuterich's court-martial is scheduled to begin March 3.