PHOENIX (AP) -- Authorities say they've arrested a man accused of shooting at an off-duty Maricopa County sheriff's deputy. Phoenix police announced Friday that 27-year-old John William Murphy is being held on suspicion of aggravated assault, drive-by shooting and unlawful discharge of a weapon. Murphy was originally arrested for prohibited possession of weapons. Police say the 32-year-old deputy had just finished his shift about 7 a.m. Tuesday. His 51-year-old uncle went on a ride-along with him. The men were returning to a family member's home when they saw a pickup truck parked facing the wrong direction in front of the house. A chase ensued and the driver of the truck allegedly fired at the deputy's vehicle. The bullet shattered the driver's side window and slightly injured the deputy. The deputy's uncle wasn't hurt.