A U.S. military commander altered a report on a firefight in Afghanistan to cast blame for the death of a Delta Force commando on a Canadian youth who was captured after the shooting stopped, a defense attorney said Thursday.

The attorney, Navy Lt. Cmdr. William Kuebler, made the allegation at a pretrial hearing as he argued for access to the officer, identified only as "Col. W," as well as details about interrogations that he said might help clear his client of war-crimes charges.

The U.S. military has charged Omar Khadr with murder for throwing a grenade that killed Sgt. 1st Class Christopher Speer during a U.S. military raid on July 27, 2002, on an al-Qaida compound in eastern Afghanistan. Khadr's case is on track to be the first to go to trial under a military tribunal system at this U.S. Navy base in southeast Cuba.

The military commander's official report the day after the raid originally said the assailant who threw the grenade was killed, which would rule out Khadr as the suspect. But the report was revised months later, under the same date, to say a U.S. fighter had only "engaged" the assailant, according to Kuebler, who said the later version was presented to him by prosecutors as an "updated" document.