While taking questions from reporters during Friday's news conference, Col. Steven McCraw of the Texas Department of Public Safety criticized some aspects of the police response to the shooting, in particular regarding the time it took for officers to engage with the gunman.
"A decision was made that this was a barricaded subject situation," McCraw said of the incident commander's "thought process" at the time.
Rather than immediately try to breach the classroom and engage with the gunman, McCraw said the commander — who he later identified as the school district's chief of police — decided that "there was time to retrieve the keys, and wait for a tactical team with the equipment to go ahead and breach the door and take on the subject."
"From the benefit of hindsight where I'm sitting now, of course it was not the right decision. It was the wrong decision, period. There's no excuse for that. But again, I wasn't there," he added.
"We believe there should have been an entry as soon as you can," McCraw continued. "When there's an active shooter, the rules change."
The revelation explains the lengthy wait between when officers first arrived to the school at 11:44 a.m. local time and when a tactical team finally entered the room and killed the gunman at 12:50 p.m. local time. The tactical team was able to enter using keys from a janitor, McCraw said.
Hear the Texas official during the press conference here:
CNN's Nora Neus, Eric Levenson, Michelle Krupa and Elizabeth Wolfe contributed reporting to this post.