WASHINGTON, Nov. 13 — Federal agents investigating the Sept. 16 episode in which Blackwater security personnel shot and killed 17 Iraqi civilians have found that at least 14 of the shootings were unjustified and violated deadly-force rules in effect for security contractors in Iraq, according to civilian and military officials briefed on the case.

The F.B.I. investigation into the shootings in Baghdad is still under way, but the findings, which indicate that the company’s employees recklessly used lethal force, are already under review by the Justice Department.

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. Spokesmen for the Justice Department and the F.B.I. declined to discuss the matter.

The case could be one of the first thorny issues to be decided by Michael B. Mukasey, who was sworn in as attorney general last week. He may be faced with a decision to turn down a prosecution on legal grounds at a time when a furor has erupted in Congress about the administration’s failure to hold security contractors accountable for their misdeeds.