WASHINGTON (CNN) -- Flying over Haditha, Iraq, on November 19, 2005, a small, unmanned spy plane called "Scan Eagle" recorded scenes of heavy fighting -- bombings and strafings from the air, and ground work by U.S. Marines seeking insurgents who earlier in the day had set off a roadside bomb that killed one of their members.
Lawyers for Marine Corps Staff Sgt. Frank Wuterich will introduce video of Haditha taken by a drone as evidence.
Shortly after the bomb attack, Marines hunting the attackers killed 24 Iraqi civilians, leading to murder charges against four Marines a year later.
Charges against two of those Marines have been dropped -- one in exchange for his testimony and the other because a hearing officer decided that he followed rules of engagement.
The Scan Eagle arrived about 30 minutes after the initial bomb attack on the Marines and does not show the the civilians being killed. Watch video from the drone and a report about it »
It does show a house from which the military suspected insurgents triggered the bomb -- and the wrecked vehicle it left 1,000 yards (about 900 meters) away.
CNN has learned that the Scan Eagle's video -- obtained exclusively by the network -- will be introduced as evidence by lawyers for Staff Sgt. Frank Wuterich, who is facing 17 murder counts and charges of making a false official statement and trying to get another Marine to make a false statement.
The video appears to show that, throughout that day, Marines engaged in fierce firefights and called in air strikes to level buildings -- often with no definitive idea of who was inside.
That could buttress defense arguments that Marines clearing buildings on the ground with guns and grenades were just following rules of engagement.
"The defense can say, 'Hey, look, you had to do this later in the day, what's the difference between what happened later in the day and what our guys did earlier in the day?' " asked retired Marine Lt. Col. Gary Solis, a former prosecutor and military judge who teaches law at Georgetown University and West Point.
Solis, who analyzed the video for CNN, said the intense fighting and necessity of making split-second decisions could play out in favor of defendants in the case.
"You have a military jury, probably most of whom, if not all of whom, will have been in Iraq," he said.
The video shows a white sedan and the bodies of five Iraqi men who Marines said refused to lie down and were shot while running away. Villagers countered that the men were students in a taxi, but the Marines said their actions were consistent with insurgents about to detonate a car bomb.
"Every person you see on the street, every item, everything you see in the street, may be the means of your death," Solis said.
But while prosecutors may be having a hard time winning convictions, Solis believes someone should be accountable for the 24 civilian deaths in Haditha.
"It be would be difficult to say justice has been served if no one is convicted in Haditha," he said.
In addition to the four Marines initially charged with murder, four officers were charged with failing to properly investigate and report the killings. Charges against one of those officers have been dropped.
Asked for a comment, military prosecutors said through a spokesman they are prohibited from discussing evidence in the case. Pentagon officials simply declined to comment.
Haditha, which lies along the Euphrates River, was the target of previous Marine campaigns aimed at rooting out insurgents.
The service launched its investigation into the killings in March 2006, after an Iraqi human-rights group raised allegations that the Marines had gone on a house-to-house rampage after the bombing, and brought charges the following December.
Supporters of the men have argued that they were being railroaded by the government.
A statement from the Marine Corps originally blamed the civilian deaths on the same roadside bomb that killed a member of the detachment, triggering a parallel investigation into how commanders handled the incident.
Murder charges remain against Wuterich and Lance Cpl. Stephen Tatum. The officers charged in the incident are Lt. Col. Jeffrey Chessani, the battalion commander, Capt. Lucas McConnell and 1st Lt. Andrew Grayson. E-mail to a friend