A military judge has refused to dismiss charges against the highest ranking officer accused of wrongdoing following the killing of two dozen Iraqi civilians in the city of Haditha two years ago.

The judge, Col. Stephen Folsom, rejected attempts by attorneys for Lt. Col. Jeffrey Chessani to throw out the case or order that a new pretrial investigative hearing take place to determine if the charges against him should stand.

Chessani was the battalion commander at Haditha when a squad of Camp Pendleton Marines killed the civilians following a roadside bombing and small arms attack on Nov. 19, 2005.

The civilian deaths occurred as troops searched for their attackers. Those killings and the actions of commanders in the aftermath have led to the largest criminal case against Marines since the invasion of Iraq in 2003.

One of Chessani's attorneys, Brian Rooney, said Wednesday that Folsom has refused to allow a deposition be taken from U.S. Rep. John Murtha, D-Pa., as part of the defense's motion to have the case dismissed on the basis the charges resulted from "undue command influence."

The judge refused the defense access to computer hard drives of commanders above Chessani containing e-mail messages about the incident. Chessani's attorneys contend those messages show that their client had fully reported what he knew and that commanders far above him, including at least two generals, had concluded no formal investigation into the civilian deaths was required.

"That was the most stunning part of the ruling," Rooney said. "We intend to file a motion asking the judge to reconsider that because the essence of the case is all about the reporting."

Chessani, who commanded Camp Pendleton's 3rd Battalion, 1st Marine Regiment at Haditha in November 2005, is charged with dereliction of duty and failing to accurately report and thoroughly investigate a possible war crime. His scheduled to go on trial by military court-martial on April 28.

Two Marines under his command, Staff Sgt. Frank Wuterich and Lance Cpl. Stephen Tatum, face court-martials this spring on manslaughter charges in the civilian deaths.

Richard Thompson, chief counsel of the Christian-based Thomas More Law Center of Ann Arbor, Mich., that is representing Chessani, said the pretrial rulings against Chessani and the prosecution itself "stink to high heaven."

"Denying us the right to take Murtha's deposition so that we could show undue command influence, as well as denial of our request for production of documents in the possession of Lt. Col. Chessani's superiors, makes it impossible for us to render this loyal Marine officer the effective assistance of counsel he deserves," Thompson said in a written statement. "They are attempting to throw him under the bus."

A second officer also accused of wrongdoing at Haditha, 1st Lt. Andrew Grayson, has been in a Camp Pendleton courtroom this week for a motion hearing in advance of his trial.