Elijah Loren Arthur and Joey Michael Thomas have pleaded not guilty to murder and weapons charges in the May 24 death of Jair Cabrera of the Salt River Police Department.
Cabrera was shot at a convenience store where the stop was made.
Authorities say Arthur shot the officer before Cabrera got out of his car.
Thomas is accused of supplying the rifle, driving the car stopped by Cabrera and baiting the officer into the stop.
Investigators say Arthur acknowledged shooting at the store's gas pumps but said he didn't intend to shoot Cabrera.
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