ESCONDIDO — Escondido police are investigating after an officer heard a gunshot while chasing a suspected thief from Palomar Hospital on Friday afternoon. Officers initially went to the hospital, on Citricado Parkway, after someone reported that a bag had been stolen, an Escondido police sergeant said. When police arrived, the suspected thief ran into bushes near the hospital, police spokesman Lt. Bode Berreth said. One of the officers chasing him heard a gunshot. Police set up a perimeter in residential neighborhood just east of the hospital and are continuing to search for the suspected thief and the source of the gunshot.