When asked how much time passed between the gunman arriving at the school and the gunman being killed, Texas’ Director of Public Safety Steve McCraw offered an indefinite response.

“Forty minutes, an hour,” he said. “But I don’t want to give you a particular timeline.”

“Bottom line, law enforcement was there, they did engage immediately, they did contain him in a classroom,” he added. “They put a tactical stack together, in a very orderly way, and breached and assaulted the individual.”

It’s unclear how long the shooter was in that classroom until a tactical unit arrived on the scene. It’s also unclear how many children were in that classroom.