An 18-year-old Maryville student has been charged with the first degree murder of a teen. William Riley Gaul, a freshman football player at Maryville College, is suspected of firing a gun into the bedroom of 16-year-old Emma Walker. Investigators believe that she was killed while she was asleep. Gaul was taken into custody at Woodlands Apartments. They also believe he tried to tamper with evidence related to the case. The victim was a student at Central High School, the same school that Gaul attended. No motive has been released at this time. Gaul is being held on a $750,000 bond at the Knox County Jail.