Did Marines go wild, or simply follow the rules?

Did a brand-new Marine Special Operations unit run amok in eastern Afghanistan in March, firing indiscriminately at civilians along a 10-mile stretch of highway?

Or did the Marines, having just survived a suicide car bomb, return fire at insurgents who shot at them as their six-Humvee convoy tried to escape a well-planned ambush near Jalalabad?

That was the issue facing three veteran combat officers who heard three weeks of vague and often contradictory testimony in a court of inquiry. Hanging over the inquiry was a more elemental question confronting all investigations of alleged misconduct by U.S. forces in Iraq and Afghanistan: Can any investigation really get to the truth of what happens during highly charged combat situations against grinding insurgencies thousands of miles away?

The panel tried mightily, slogging through nearly 50 witnesses over 17 days. But the officers, who will report their findings to a Marine general, had to contend with flawed memories and missing evidence -- what a government lawyer attributed to the "fog of war":

* Naval Criminal Investigative Service agents did not arrive on the scene until two months after the March 4 incident, and they spent just an hour there.

* The head of an Army investigation let the local Afghan governor determine who had been killed or wounded and, according to defense lawyers, did not challenge or investigate statements by purported Afghan witnesses.

* Afghan doctors at two hospitals where the victims were reportedly treated did not ask how their patients were wounded, or even whether they had been at the shooting site.

* There were no autopsies, no detailed medical records and no forensic evidence from the shooting site.

* Some 125 shell casings collected at the site were inadvertently dumped into a fire pit and burned.

* Several Marines from the 30-man convoy testified that they couldn't see much from inside their cramped Humvees, yet they insisted that gunmen fired at the convoy and that Humvee gunners obeyed the appropriate rules of engagement.

* The Marines with the best view of events -- four men who fired their weapons -- didn't testify because they did not have immunity from prosecution.

* A Pashtun elder who said Marines shot up his car without provocation, killing his father and nephew, gave contradictory accounts -- and made the astonishing claim that his car was hit by "thousands and thousands" of bullets.

Given these and other shaky investigative building blocks, it's not surprising that a Naval Criminal Investigative Service agent seemed ready to toss up his hands in frustration. "We were trying to put pieces together and some of them just don't fit. We're not sure of anything," agent David Kurre told the panel.

One panel member responded: "That's the most accurate statement I've heard in the court so far."

The court of inquiry is a fact-finding body, not a court of law. No one has been charged in the case; Marine Lt. Gen. Samuel Helland will decide on any further action after reviewing the panel's report.

The inquiry investigated the actions of Maj. Fred C. Galvin, commander of Fox Company, and the convoy commander, Capt. Vincent J. Noble. The unit, the first Marine Special Operations company deployed in combat, had been in Afghanistan three weeks at the time of the incident.

The inquiry was prompted by two early descriptions of the shootings that described high civilian casualties.

An Afghan human-rights commission, quoting Afghan civilians and officials, said the Marines fired indiscriminately along 10 miles of highway, killing at least 12 civilians and wounding 35.

The U.S. Army commander in the area, Col. John W. Nicholson, said in May that 19 civilians were killed and 50 wounded -- figures provided by the Afghan governor.