The Sheriff's Department is investigating an apparent homicide after responding to a traffic accident involving a taxi cab and discovering the driver had been shot.  Lemon Grove firefighters responded to the rollover vehicle accident, about 3:50 a.m. near the intersection of Main Street and Broadway Avenue. The cab driver was removed the vehicle and paramedics observed a bullet wound to his upper body.  The male victim died at the scene. Authorities said they're investigating the case as a homicide.  Anyone with information is asked to call Crime Stoppers at (888) 580-8477.