(CNN) -- One of three Afghan civilians wounded when U.S. contractors shot at them in an incident in early May died of his wounds Sunday, according to U.S. military officials in Afghanistan.
A second Afghan civilian remains in serious condition, and the third person wounded was treated and released from a Kabul hospital, according to the U.S. military in Kabul.
The incident, which happened in Kabul on May 5, remains under investigation by the U.S. military in Afghanistan.
Meanwhile, three of the four contractors involved in the shooting have left the country, according to the California lawyer who says he represents them. Two are back in the United States already.
The attorney, Dan Callahan from Callahan & Blaine law firm, told CNN that his clients were transporting interpreters when the incident happened.
While he has not spoken to the other two contractors in a few days, Callahan said he believes they, too, have left.
After the shooting, the men claimed they were being held against their will by their former employer, Paravant, in Kabul. Paravant's parent company, Xe, said the men were not being held against their will. It said the U.S. military told the company to instruct the men to stay as the investigation progressed.
The U.S. military denied the men were being asked to stay because of the investigation, and the contractor's lawyer said his repeated request for clarification from the military yielded no answer, so he told his clients they could leave the country.
"All I got from the government is that there is an investigation ongoing," Callahan said. "I take that to mean there are no charges or orders to stay."
The contractors were working for Paravant to train Afghan national army soldiers on weapons, according to the U.S. military. Paravant is affiliated with Xe, the new company name for the security contractor Blackwater Worldwide.
Xe spokeswoman Anne Tyrrell said the four men had their contracts terminated "for failure to comply with the terms of their contract, which require, among other things, compliance with all laws, regulations and company policies."
The contractors told their lawyer they believe Xe was concerned that they had been given guns without a license to carry them, according to Callahan.
Xe employees are not banned from carrying weapons in Afghanistan, and it "depends on the task we were hired to perform," Tyrrell said. The company has not commented on the terms of this specific contract or said whether it issued guns to the men.
The U.S. military told CNN the contractors were likely allowed by the terms of the contract to possess privately owned weapons.
"We are still not 100 percent sure that they were authorized, but it looks like they probably were," said Lt. Col. Christian Kubik, a spokesman for the U.S. military in Afghanistan.
Callahan said that while the contractors were in Afghanistan, Xe had been interviewing them about the May 5 incident in Kabul.
He said the contractors acted appropriately in the incident, which began after a traffic accident in which a car slammed into one of two contractors' cars. The contractors got out to help their colleagues, according to Callahan.
"The attacking vehicle did a U-turn and headed back at them, so they shot," he said.
The U.S. military, in describing the incident in a news release, said that the car was in an accident but did not describe how the accident happened. However, the military statement provided a similar account of what happened after the accident, saying the contractors "were approached by a vehicle in a manner the contractors felt threatening."
All four contractors are U.S. military veterans and had been working for Paravant in Afghanistan for six months, according to Tyrrell. None of them has worked for Xe or its other subsidiaries, including Blackwater, she said.
An industry source familiar with the incident said all four contractors were on their first deployment with the company.