NORTH MIAMI BEACH, Fla. (AP) — A Miami city police officer was found shot to death in his unmarked patrol car early Tuesday, authorities said.

Detective James Walker, 30, was found in an alley by North Miami Beach officers responding to reports of shots fired around 12:30 a.m., said Miami police spokesman Lt. Bill Schwartz. It wasn't known if Walker returned fire, he said.

Police were searching for a suspect in a white Ford Taurus with bullet holes, but they didn't release details on the gunman. Blood trails led from Walker's car, and a high-powered rifle was found at the scene.