Police responded to an active shooting at Columbia Mall in Maryland shortly after 11:00 a.m. ET. Three people are confirmed dead and the mall remains on lockdown. UPDATE, 12:40p ET: People inside the mall are being told to wait until they are escorted out. The scene is believes to be secure. UPDATE, 12:34p ET: Randy Brooks, owner of Edward Arthur Jewelers at Columbia Mall, told Uma Pemmaraju that he heard a couple of pops and then saw people running. He said it appeared that the shooter had a shotgun and was killed, but police have not confirmed that. Brooks said...