A 21-year-old airman has been identified as the shooter early this morning at the Wal-Mart Supercenter in south Grand Forks. Marcell Willis was on active duty at Grand Forks Air Force Base, according to a police statement released this afternoon. Police are still investigating the motive behind the shooting, but there doesn't appear to be a link between Willis and the store employees, Grand Forks Police Lt. Derik Zimmel said. According to police, Willis entered the store, 2551 32nd Ave. S., just after 1 a.m. and shot two employees, including one fatally. He also shot but missed another Wal-Mart employee...