On October 2, 2012, 30-year-old Border Patrol Agent Nicholas J. Ivie was killed in a remote Arizona canyon near the Mexican border while responding to a triggered ground sensor in a known smuggling corridor. Ivie, a native of Provo, Utah, had served four years at the Brian A. Terry Border Patrol Station near Bisbee and left behind a wife and two young daughters.

At about 1:30 a.m., visibility was poor and the terrain was rocky when Ivie and two other agents encountered one another and mistook colleagues for hostile individuals. An exchange of gunfire ensued; Ivie was mortally wounded and a second agent was injured but survived. Ballistic testing and the FBI investigation later determined the fatal and wounding shots were fired by another agent on scene, and investigators concluded no outside suspects were involved.

What details about that response or that night might help explain how such a mistaken-identity shooting occurred?