The U.S. military is investigating the deaths of 19 Afghans — including women and children — after an attack on a Marine convoy outside Jalalabad in March.
The incident has further strained relations between the Afghan people and the American military.
There's one fact everyone agrees on: The Marine unit was attacked by a suicide car bomber. But there's a dispute about what happened next.
The Marines say they were attacked by insurgents using AK-47s. They returned fire, killing a number of people.
But two separate investigations — the first by the Afghan Independent Human Rights Commission, the second by the American military — concluded there was no attack by insurgents using assault weapons. Both investigations said Marines fired for at cars and people for miles as they headed back to the base.
No American military official would discuss the ongoing criminal investigation.
James Culp, a lawyer for one of the Marines, says insurgents attacked:
"There were several insurgents, Taliban members, Afghan males that were firing in the direction of the vehicles," Culp says.
Culp won't reveal his client's name, other than to say he's a Marine sergeant in his late 20s who also served a tour in Iraq.
He says the man he's representing was part of an elite unit — two dozen Marines in all — who rode in that convoy. Culp says his client was careful only to shoot those who were a threat.
"My client did not shoot women or children," he says.
A dozen Naval criminal investigators are now gathering evidence along the route the Marines took after the attack. NPR has learned investigators are focusing on six of those Marines.
The handling of the investigation is also creating tensions within the military.
Army Col. John Nicholson told families of Afghans killed at the hands of Marines that he was "deeply, deeply ashamed and terribly sorry that Americans have killed and wounded innocent Afghan people."
He referred to the "death and wounding of innocent Afghans" as "a stain on our honor and on the memory of many Americans who have died defending Afghanistan and the Afghan people."
And he branded the incident "a terrible, terrible mistake."
Those words were too much for the top Marine officer, Gen. James Conway, who says Nicholson should not have said a mistake was made or apologized.
"I think he was premature to apologize, in that there is an investigation ongoing to determine what happened," Conway said.
The first American military found no brass shell casings near the scene. That raised doubts about whether the Marines were even attacked by small arms fire.
But law professor Gary Solis says evidence could have disappeared because military investigators showed up two days after the attack.
"People are going to pick up things like brass," Solis says. "Blood pools are going to disappear. Bullet holes against buildings."
Solis is a former Marine officer who now studies war crimes. He says the lack of brass casings at the scene does not mean there was no ambush.
The criminal investigation is focusing on whether Marines overreacted. Some reports say they kept firing for up to 10 miles along the road after the attack.
The Jalalabad attack is one of several recent incidents which American or NATO troops are accused of killing innocent Afghan civilians. And defense lawyer Culp says his client is being targeted for political reasons.
"I believe these young Marines were thrown under the bus," Culp says. "The Americans had to quickly respond to that in a way to appease the Afghans."
Fighting an insurgency within a civilian population is one of the military's toughest challenges.
Gen. Frank Kearney is in charge of all special operations forces in Afghanistan and ordered the criminal investigation. He says he's working closely with the Afghan government to make sure that innocent civilians are not caught in the crossfire.
Meanwhile, the criminal investigation is expected to wrap up sometime this summer. Then senior officers will decide whether some of the Marines in that convoy should be charged.