It would be a familiar scene in Iraq's next few years: Crowds gather, insurgents mingle with civilians. Troops open fire, and innocents die.
All the while, according to internal military correspondence obtained by The Associated Press, U.S. commanders were telling Washington that many civilian casualties could be avoided by using a new nonlethal weapon developed over the past decade.
Military leaders repeatedly and urgently requested the device. It uses energy beams instead of bullets and lets soldiers break up unruly crowds without firing a shot.
It is a ray gun that neither kills nor maims, but the Pentagon has refused to deploy it because of the possibility that the weapon might be seen as a torture device.
Perched on a Humvee or a flatbed truck, the Active Denial System gives people hit by the invisible beam the sense that their skin is on fire. They move out of the way quickly and without injury.
On April 30, 2003, two days after the first Fallujah incident, Gene McCall, then the top scientist at Air Force Space Command in Colorado, typed out a two-sentence e-mail to Gen. Richard Myers, chairman of the Joint Chiefs of Staff.
"I am convinced that the tragedy at Fallujah would not have occurred if an Active Denial System had been there," McCall told Myers, according to the e-mail obtained by AP. The system should become "an immediate priority," McCall said.
Myers referred McCall's message to his staff, according to the e-mail chain.
McCall, who retired from government in November 2003, remains convinced the system would have saved lives in Iraq.
"How this has been handled is kind of a national scandal," McCall said by telephone from his home in Florida.
A few months after McCall's message, in August 2003, Richard Natonski, a Marine Corps brigadier general who had just returned from Iraq, filed an "urgent" request with officials in Washington for the energy-beam device.
The device would minimize what Natonski described as the "CNN Effect": the instantaneous relay of images that depict U.S. troops as aggressors.
A year later, Natonski, by then promoted to major general, again asked for the system, saying a compact and mobile version was "urgently needed," particularly in urban settings.
Natonski, now a three-star general, is the Marine Corps' deputy commandant for plans, policies and operations. He did not respond to an interview request.
In October 2004, the commander of the 2nd Marine Expeditionary Force "enthusiastically" endorsed Natonski's request. Lt. Gen. James Amos said it was "critical" for Marines in Iraq to have the system.
Senior officers in Iraq have continued to make the case. One December 2006 request noted that as U.S. forces are drawn down, the nonlethal weapon "will provide excellent means for economy of force."
The main reason the tool has been missing in action is public perception. With memories of the 2004 Abu Ghraib prison scandal still fresh, the Pentagon is reluctant to give troops a space-age device that could be misconstrued as a torture machine.
"We want to just make sure that all the conditions are right, so when it is able to be deployed the system performs as predicted - that there isn't any negative fallout," said Col. Kirk Hymes, head of the Defense Department's Joint Non-Lethal Weapons Directorate.
Reviews by military lawyers concluded it is a lawful weapon under current rules governing the conflicts in Iraq and Afghanistan, according to a Nov. 15 document prepared by Marine Corps officials in western Iraq.