PHOENIX – A probe into the killing of a Border Patrol agent in an apparent “friendly fire” death has revealed he was in radio contact with other agents on the scene before the fatal shooting last month in southern Arizona, local media reported.

A report on Friday from the Cochise County Sheriff’s Office said agent Nicholas Ivie and two fellow agents involved in the pre-dawn incident were responding to a tripped sensor near the U.S.-Mexico border, Phoenix television station ABC15 said on its website.

The sheriff’s report also said one of the two other agents, both of whom had approached the scene in darkness from the opposite direction as Ivie, told investigators she had observed Ivie “signaling them with his flashlight.”

Ivie, 30, ended up being shot to death in a burst of gunfire in the desert near Naco, Arizona, a spot well-known for drug – and human-trafficking.

A second agent was shot and wounded, while the third, who reported seeing Ivie’s flashlight beam, was unscathed.

The information about the radio contact and other details of what transpired in the early morning hours of October 2 were brought to light in statements made to investigators by the uninjured female agent, the television station reported.

After joining up with the second agent by vehicle and proceeding together on foot, she saw muzzle flashes and gunfire as she walked up a trail, then took cover. The report said she drew her weapon but was not clear on whether she opened fire.

“She thought she observed three to four people moving in the area, but she could not describe them,” the report was quoted as saying. “She also mentioned hearing whispering. She could not say if it was in English or Spanish.”

Sean Chapman, an attorney for the wounded agent, has told Reuters it was likely Ivie was shot after being mistaken for a smuggler in the darkness, and only fired his weapon after being shot in the ankle and buttocks.

The agent’s shooting remained under investigation by the FBI. An FBI spokesman in Phoenix declined comment on the sheriff’s office report.

The FBI has said there were strong preliminary indications that Ivie’s death was the result of friendly fire in an accidental shooting in which only Border Patrol agents were involved. It has released scant details on what its investigators know of the circumstances.

(Reporting by David Schwartz; Editing by Steve Gorman and Todd Eastham)