BAGHDAD, Iraq – The U.S. military has concluded its investigation into a video that appeared to show private security contractors shooting at civilian vehicles driving on highways in Iraq and determined that no one involved will be charged with a crime, a military spokesman in Baghdad said.

Agents with the Army’s Criminal Investigation Division “reviewed the facts available concerning the incident to determine if there was any potential criminality that falls within CID’s investigative purview,” Maj. Timothy Keefe said in a written statement.

“The review determined that no further investigative effort on the part of Army CID was warranted.”

No security contractor has been prosecuted for such incidents, in part because of an agreement forged soon after the U.S. invasion in 2003 that made it impossible for the Iraqi government to prosecute contract workers. While several contractors have been relieved of their duties for shooting without cause, actions taken against contractors are generally carried out quietly and rarely, if ever, disclosed.

The investigation, which officials have not released or previously discussed publicly, began after the video was posted on an Internet site purportedly run by employees of Aegis Defense Services, a London-based firm with a $293 million U.S. government security contract.

The initial online version of the video, posted in late 2005 on the site, contained several brief clips of cars being strafed by machine-gun fire, set to the music of the Elvis Presley song “Mystery Train.” A version posted months later contained laughter and the voices of men joking with one another during the shootings.

Keefe said that the “alleged shooter” in the video was determined to be South African. Investigators said they believe British and South African authorities “will come to the same conclusion that CID did as to the lack of probable cause to believe that a crime was committed,” Keefe’s statement said.