State Police are investigating an accident in Augusta County that killed a Staunton boy and seriously injured his mother. Police say the single-vehicle crash occurred at 8:15 p.m. Saturday on Route 720 in Augusta. 32-year-old Stephanie D. Dudley was driving a Ford Mustang that veered off the road and didn’t stop until it hit a tree. Her 3-year-old son, Karl A. Swanson, Jr., died at the scene. The boy was in a child safety seat. His mother was flown to UVA Hospital for treatment of life-threatening injuries. She was not wearing a seat belt, and charges are pending.