Texas officials have launched an investigation into the Uvalde police response to the shooting at Robb Elementary School on Tuesday after conflicting statements over whether cops fired at the gunman as he made his way inside.
Salvador Ramos, 18, arrived at the school in Uvalde at 11.30am, crashing his car into a ditch.
A school resource officer was at the scene but he failed to stop him from making his way inside.
Two other cops also rushed to the school at that time - Ramos had just shot his grandmother in the face at their home less than five miles away. She survived and called the police.
It was first reported that those cops exchanged gunfire with Ramos, but police now say they cannot confirm that.
Ramos went on to barricade himself inside the classroom, killing 19 kids and two teachers, before a SWAT team breached the door and shot him around an hour later.
Sources say police were struggling to get into the classroom and needed a key to open the door.
Eventually, a border patrol agent was able to get inside and the shooting was declared over at 1.06pm.
But it questions remain over why it took police so long to get into the classroom where the kids were trapped with the gunman.
Frustrated parents were standing outside the school begging cops to go inside when the shooting was unfolding.
Javier Cazares, whose nine-year-old daughter was murdered, says cops were 'just standing there' and waiting for protective shields to arrive at the scene before they went in.
'They said they rushed in and all that, we didn’t see that,' he told The New York Times, adding that many were 'just standing there.'
'There were plenty of men out there armed to the teeth that could have gone in faster. This could have been over in a couple minutes,' he said.
He added that police were faster to escort Beto O'Rourke out of the press conference yesterday when he started heckling the governor than they were to get into the school.
Angel Garza, whose daughter was killed, was handcuffed after trying to run into the school when he heard that a 'girl called Amerie' had been shot. He later found out that she was among those who died while giving medical aid to other children who escaped.
Derek Sotelo, 26, who works in a tire shop nearby, said parents were begging to be let into the school.
'They were just angry, especially the dads. We were wondering, "What the heck is going on? Are they going in?" 'The dads were saying, "Give me the vest, I’ll go in there!'