DOWAGIAC -- Dowagiac police are investigating a homicide case.  They say 28-year-old Darius Nickens was shot to death in a driveway in the 200-block of Grand Boulevard late Wednesday afternoon.  He was found under a car, with a single gunshot wound.  He was unresponsive and later pronounced dead at the hospital.  Police were seeking a suspect in a stolen 2005 Chevy Malibu, but the car was later found abandoned in Elkhart, Indiana.