AUSTIN, Texas (AP) — The head of the Texas Department of Public Safety says three minutes after a gunman entered a school where he slaughtered 19 elementary students and two teachers there was sufficient armed law enforcement on scene to stop the gunman.

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Yet police officers armed with rifles stood and waited in a school hallway for more than an hour while the gunman carried out the massacre.

Col. Steve McCraw, director of the Texas Department of Public Safety, called the police response "an abject failure."

He says police radios did not work within the school and that school diagrams officers used were wrong.