School police officer ‘confronted’ shooter but didn’t fire at him before deadly attack

Parents reportedly broke school windows in an attempt to reach their children inside

Chilling footage has surfaced of Salvador Ramos, 18, stalking around the outside of Robb Elementary School in Uvalde, Texas, while carrying a rifle just before he killed 19 children and two adults in a mass shooting.

Just before arriving at the school, Ramos had reportedly gotten into an argument with his grandmother. Those who knew Ramos said he was frequently bullied for a speech impediment and had such a bad relationship with his mother that the state moved him out of her house so he could live with his grandmother.

The argument with his grandmother was reportedly about the fact that he would not be among the seniors graduating from the local highschool several days later. Ramos had missed large swaths of the school year and was not cleared to receive his diploma. The argument became heated, and Ramos shot his grandmother in the face, leaving her lying on the floor of her home in critical condition.

Ramos then took his grandmother's car and crashed it outside Robb Elementary School, where he was later captured on video stalking around the building.

A bystander heard the crash and called 911. Responding police reportedly confronted but did not shoot Ramos, who opened fire and hit two officers. He then fled inside the school through a backdoor and barricaded himself in a classroom, where he killed 19 students and two adults.

After about half an hour a group of Border Patrol agents working nearby responded to the scene. One of the agents rushed in and was injured, but ultimately managed to kill Ramos.

First responders described the scene at the school as "chaos" as concerned parents rushed to the building to find their children. According to reports from the responders, some parents went so far as to smash school windows to try to help their children escape.

Within an hour of the first reports of a shooting at the school, helicopters were flying overhead and nearly 500 first responders from surrounding communities — some as far as San Antonio, 85 miles away — had arrived to assist.

"I was stabilising a little girl, she was so tiny," an EMT who wanted to be identified only by his first name, Rey, told PEOPLE. "There was blood everywhere. She had been shot in the chest and the shoulder. We were trying to stop the bleeding. I looked at her and I was like 'She's just a baby. Who would shoot a baby?'"

Parents waited for hours to be reunited with their children, and those whose children were being treated at local hospital ERs waited even longer for news about their children's conditions.

By late Tuesday afternoon Texas Governor Gregg Abbott confirmed that 14 children had been killed. That number later grew to 19.

On Wednesday, Mr Abbott held a press conference addressing the shooting, and said “mental health” was the driving force behind the shooting. He was confronted during that conference by Texas gubernatorial candidate Beto O’Rourke, a Democrat, who said the shooting was “totally predicable” and was “on [Mr Abbott].”