Police officers responding to last month’s mass shooting at an Uvalde, Texas, elementary school never even tried to open the door to the classroom where young children were trapped with the gunman, according to a new report. A law enforcement source cited by the San Antonio Express-News on Saturday said surveillance footage revealed no attempts by officers to open the door during the entire 77-minute siege at Robb Elementary School. Nineteen children and two teachers were killed during that time. In the wake of the massacre, police claimed part of the reason they took so long to confront the shooter was because officers could not access the classroom and needed to wait for a key. But the law enforcement source told the Express-News that the gunman, Salvador Ramos, could not have locked the classroom door from the inside, and investigators believe it may have been open the whole time. In addition, the source said, a forcible entry tool called a halligan bar was available to officers throughout the siege, which would have allowed them to open even a locked door. The police response to the deadly attack is currently under investigation by the Texas Rangers and the FBI.