Steve Neavling

 A long-awaited autopsy has revealed that a U.S. Border Patrol agent died of a gunshot wound to the head by what federal authorities describe as friendly fire along the Arizona-Mexico border, CNN reports.

The report, released Wednesday, shows that Nicholas J. Ivie, 30, of Provo, Utah, died Oct. 2 by a “penetrating gunshot wound of the head involving the brain.”

Ivie was responding to an alarm at the border when he became involved in a shootout that also wounded another agent.

In a preliminary investigation, the FBI said evidence suggests the shooting was between Border Patrol agents who had become confused.