The gunman who killed 21 people inside a Uvalde elementary school walked into the unlocked building unopposed, the Department of Public Safety said in a revised statement, as reported by the Austin American-Statesman and other media sources.After the gunman crashed his grandmother’s truck in a ditch, he walked into the building while firing a semiautomatic weapon purchased just days after his 18th birthday. The shooter was inside a classroom for about an hour. Nineteen children and two teachers were killed before a tactical team got inside the building and killed him.The massacre is the second-deadliest school shooting in modern U.S.