FBI agents investigating a shooting in Iraq in which US private security firm Blackwater shot and killed 17 Iraqi civilians have found that at least 14 of the shootings were unjustified.
According to a report in The New York Times, while the FBI investigation into the shootings in Baghdad is still under way, the findings, which indicate that the company's employees violated deadly force rules in effect for security contractors in Iraq, are already under review by the Justice Department.
It cited unnamed civilian and military officials briefed on the case.
Prosecutors have yet to decide whether to seek indictments, and some officials have expressed pessimism that adequate criminal laws exist to enable them to charge any Blackwater employee with criminal wrongdoing, the Times reported.
North Carolina-based Blackwater protects US diplomats and other State Department officials in Iraq.
Spokesmen for the Justice Department and the FBI declined to discuss the matter, the paper said.
The case could be one of the first thorny issues to be decided by Michael Mukasey, who was sworn in as US attorney general last week.
He may be faced with a decision to turn down a prosecution on legal grounds at a time when a furore has erupted in Congress about the administration's failure to hold security contractors accountable for their misdeeds, the Times said.
Investigators have concluded that as many as five of the company's guards opened fire during the shootings.
They found no evidence to support assertions by Blackwater employees that they were fired upon by Iraqi civilians. That finding sharply contradicts initial assertions by Blackwater officials, who said that company employees fired in self-defence.
Government officials said the shooting occurred when security guards fired in response to gunfire by other members of their unit in the mistaken belief that they were under attack. One official told the Times: "I wouldn't call it a massacre, but to say it was unwarranted is an understatement."
Among the 17 killings, three may have been justified under rules that allow lethal force to be used in response to an imminent threat, the FBI agents have concluded, the Times said.
A separate military review of the shootings concluded that all of the killings were unjustified and potentially criminal.
Anne Tyrrell, a Blackwater spokeswoman, told the Times she would have no comment until the FBI released its findings.