On Dec. 14, 2012, a 20-year-old gunman identified as Adam Lanza forced his way into Sandy Hook Elementary School in Newtown, Conn., where he killed 20 children and six adults with a high-power rifle before taking his own life. The investigation found Lanza had also killed his mother shortly before the shooting at the school.

Police: Students, Staff Shot at Conn. School

Connecticut state police Lt. Paul Vance says that staff and students at Sandy Hook Elementary School in Newtown are among the victims of a school shooting. Vance also says the shooter was dead in the school.