NOGALES, Ariz. (AP) — A rancher who lives near Arizona’s border with Mexico is being held on a charge of first-degree murder in last week’s fatal shooting of a man tentatively identified as a Mexican citizen. His bail was set at $1 million.

The Santa Cruz County Sheriff’s office in Nogales, Arizona, confirmed Monday that George Alan Kelly, 73, was arrested last week in the killing. Authorities believe the victim was Gabriel Cuen-Butimea, 48, who lived just south of the border in Nogales, Mexico, because of a Mexican voter registration card he carried.

The killing occurred Jan. 30 in the Kino Springs area just outside Nogales, Arizona, said Sheriff’s Chief Deputy Gerardo Castillo. The address where the killing happened is the same one listed in public records for Kelly’s cattle ranch.

Details about the shooting were sketchy and it was unknown if the two men previously knew each other. Authorities have not given a motive.

Kelly was being held at the Santa Cruz County Jail after hisarraignment in the county’s Justice Court last week. He is set to return to court Wednesday.

Local attorney Brenna Larkin, who was appointed by the court to represent Kelly, did not immediately return a call seeking comment on the charge against him.