Police responding to the mass shooting at an elementary school in Uvalde, Texas, arrived within minutes of the gunman breaching Robb Elementary School, but waited more than an hour before engaging him even though they were heavily armed with rifles and at least one ballistic shield, new documents and video footage reveals.

The footage shows officers becoming impatient, hearing gunshots inside as they wait for an order from leadership to engage with attacker Salvador Ramos, the Austin American-Statesmen reports.

That order didn’t come until nearly an hour-and-a-half after Ramos arrived on campus and shot 19 students and two teachers.

This is a breaking news story and will be updated with new information..