Thornton police are searching for Luis Arebalo, 37, after an officer was shot during an encounter Sunday night in the 12800 block of Ulster Street. Officers responded at about 9:33 p.m. Oct. 11 to a report of an unwanted person. While they were speaking with the person who called, a suspect fired multiple rounds, police said. One officer was hit, and a second officer returned fire. The injured officer was taken to a hospital with serious but non-life-threatening injuries. Investigators have not determined whether the suspect was struck by gunfire. The suspect ran from the scene, prompting police to urge nearby residents to shelter in place and others to stay away from the area. Police later lifted the shelter-in-place order. Police identified the suspect as Arebalo, who is described as 5 feet 9 inches tall and about 180 pounds, with brown hair and brown eyes. He was last seen wearing a black short-sleeved shirt and dark pants. Police say he is armed and dangerous and warn the public not to approach or try to contact him. Anyone who sees Arebalo or knows his immediate whereabouts should call 911. People with other information can contact the Thornton Police Tip Line at 720-977-5069. The investigation is ongoing.