OKLAHOMA CITY -- Police have arrested three people accused of shooting an Oklahoma City police officer Sunday night. Investigators say 27-year-old officer Katie Lawson had just finished helping an Oklahoma County Sheriff's deputy arrest a man, Hector Mercado, for DUI. Shortly after Lawson left that scene, someone with a gun opened fire on her car in the 3900 block of North Miller. Officer Lawson was hit, but managed to return fire and call for help. She's now in the hospital in good condition. Officers took three people into custody at the scene and questioned them. They later arrested 17-year-old Alex...