A police officer armed with a rifle watched the gunman in the Uvalde elementary school massacre walk toward the campus but did not fire while waiting for permission from a supervisor to shoot, according to a sweeping critique ... on the tactical response to the May tragedy. Some of the 21 victims at Robb Elementary School, including 19 children, possibly "could have been saved" on May 24 had they received medical attention sooner while police waited more than an hour before breaching the fourth-grade classroom, a review by a training center at Texas State University for active shooter situations found. The report is yet another damning assessment of how police failed to act on opportunities that might have saved lives in what became the deadliest school shooting in the U.S. since the slaughter at Sandy Hook Elementary School in 2012. The report ... follows testimony last month in which Col. Steven McCraw, director of the Texas Department of Public Safety, told the state Senate that the police response was an "abject failure." McCraw said police had enough officers and firepower on the scene of the Uvalde school massacre to have stopped the gunman three minutes after he entered the building, and they would have found the door to the classroom where he was holed up unlocked if they had bothered to check it. In the days and weeks after the shooting, authorities gave conflicting and incorrect accounts of what happened.