A sheriff says his deputies continue their methodical investigation into a shooting at a South Carolina bar that killed four people and injured 16 others. Beaufort County Sheriff P.J. Tanner says authorities are testing DNA, analyzing weapons, and enhancing video footage. He says testing physical evidence is important because none of the 700 people at the party has identified any shooter likely because they fear retribution if they talk.  No arrests have been made. The sheriff says investigators believe the shooting at Willie's Bar and Grill on St. Helena Island began as a dispute between two or three people.