PHOENIX - A probe into the killing of a US 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 US-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."

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