LOS ANGELES (AP) – The Marine Corps has dropped all charges against a captain accused of failing to investigate the deaths of 24 civilians and another Marine accused in some of the killings, the Corps announced Thursday.

Captain Randy W. Stone, 35, a battalion lawyer from Dunkirk, Md., was one of four officers charged with failing to adequately probe the killings.

“It is clear to me that any error of omission or commission by Capt. Stone does not warrant action under the Uniform Code of Military Justice,” Lieutenant General James Mattis wrote.

The Corps also announced that charges had been dismissed against Lance Corporal Justin Sharratt, who was accused of murdering three brothers in the assault that followed a deadly roadside bombing of American troops.

The decision to drop the charges against Corporal Sharratt followed an earlier recommendation from Lieutenant Colonel Paul Ware, a hearing officer.

“The government version is unsupported by independent evidence,” Colonel Ware wrote. “To believe the government version of facts is to disregard clear and convincing evidence to the contrary.”

Prosecutors alleged Sharratt and other members of his battalion engaged in a revenge-motivated assault on Iraqi civilians after a roadside bomb killed a fellow Marine. Corporal Sharratt contended the Iraqi men he confronted were insurgents and at least one was holding an AK-47 rifle when he fired at them.

Colonel Ware said prosecution of Corporal Sharratt could set a “dangerous precedent that … may encourage others to bear false witness against Marines as a tactic to erode public support of the Marine Corps and its mission in Iraq.”

“Even more dangerous is the potential that a Marine may hesitate at the critical moment when facing the enemy,” Colonel Ware said.

Besides Corporal Sharratt, two other enlisted men were charged with murder. Four officers, including Captain Stone, were accused of failing to investigate the deaths.