A teenager gunned down two people and injured a child in a horrific library shooting in Northern California late Monday. Police received reports of an active shooter at a Butte County library just past 5 p.m., and rushed to the scene after hearing a 911 call filled with screams and gunfire. Officials arrived and nabbed the shooter, 18-year-old Chico resident Bradley Scott Sayer, after he tried to leave through the back door. Sayer has been booked into the Butte County Jail on two counts of murder. The FBI is assisting in the investigation into the tragic shooting, as well as the Butte County Sheriff.