Troutsdale, Oregon police identified the gunman who killed a student Tuesday and said they discovered how he obtained his weapon. Jared Michael Padgett, 15, entered Reynolds High School with an AR-15 rifle owned by his family. He obtained it after removing it from its "secured storage place," police said Wednesday. Padgett used the AR-15 to kill himself after kiling 14-year-old Emilio Hoffman in a locker room near the school gymnasium. Teacher Todd Rispler was injured but managed to alert others that a gunman was in the school. (A handgun, nine clips, and a knife were also on Padgett.) The AR-15, a semi-automatic variant of the U.S. military's M-16 assault rifle, is considered the most popular rifle in America. It also has the infamous distinction of being the weapon of choice in recent mass shootings, most notably Adam Lanza’s murder of 26 people in Connecticut and James Holmes's killing of 16 people in Colorado. AR-15 sales were restricted under the 1994 assault weapons ban but the law expired in 2004.