Border Agents in Fatal Shooting Had Radio Contact Three U.S. Border Patrol agents responding to an alarm from a motion sensor were apparently in radio contact as they approached from opposite directions before opening fire on each other in the Arizona desert, leaving one agent dead, according to a sheriff's report released Friday. It was a clear night and the agents were on patrol separately when the call came in at about 1:30 a.m. Oct. 2. That the sensor aimed at detecting smugglers had been tripped. Agent Nicholas Ivie, 30, approached on foot from the north. The two other agents walked in from the south when Ivie apparently opened fire, eliciting a deadly barrage of return fire from his colleagues. Ivie was killed. Another agent was wounded. The third wasn't injured. Questions had swirled as to whether the agents were in communication with each other in the rugged, hilly terrain where communications can be spotty, possibly leading to the confusion and ensuing shootout. However, according to the preliminary report released Friday by the Cochise County sheriff's office, which is investigating the case along with the FBI, the uninjured agent told authorities later "they were in radio communication with Agent Ivie." "At one point she observed (Ivie) signaling them with his flashlight," according to the report. The agent, whose name hasn't been released, told investigators "as they were walking up the trail she heard yelling and then observed muzzle flashes in front of her and heard gunfire." "She drew her weapon and took cover," the report states. The agent also said she thought she saw several people moving through the darkness and whispering after the shooting. The FBI declined to comment on the sheriff's office report, noting that the agency still had its own investigation ongoing. George McCubbin, president of the National Border Patrol Council, has said Ivie apparently opened fire on the two other agents thinking they were armed smugglers, and he was killed when they returned fire. The FBI has called it a case of friendly fire but has declined to comment on any other aspects of the investigation. One sheriff's deputy noted in the report that authorities initially believed it was a "possible ambush" on the agents. In the immediate aftermath of the shooting, the Border Patrol, and other federal and local agencies flooded the area with personnel looking for the potential assailants, even bringing in air support and getting permission from Mexico to fly across the border. Two people were detained in Mexico but were later released after they were found to have no connection to the shooting. Ivie's death marked the first fatal shooting of an agent since a deadly 2010 firefight with Mexican gunmen that killed U.S. Border Patrol Agent Brian Terry in December 2010 and spawned congressional probes of a botched government gun-smuggling investigation.