A dramatic video of the Texas shooting reveals that the shooter stayed inside for 77 minutes while students yelled for help.

 On Friday, response in last Tuesday’s school massacre at Robb Elementary School in the tight-knit working class community of Uvalde, Texas as questions mount about why police didn’t engage the shooter more quickly.

Photos released on Friday were taken outside the school as the siege unfolded and show US Customs and Border Protection agents alongside local police and sheriff’s deputies, lifting children out of a window at the school.

New photos have emerged depicting part of the law enforcement response to the school massacre in Uvalde, Texas on Tuesday, as questions mount about why police didn’t engage the shooter more quickly.

The photos released on Friday were taken outside Robb Elementary as the siege unfolded on Tuesday, and show US Customs and Border Protection agents alongside local police and sheriff’s deputies, lifting children out of a window at the school.

After a siege lasting nearly an hour, it was eventually Border Patrol agents who used a master key to open the locked door of a classroom where they confronted and killed gunman Salvador Rolando Ramos, who killed 19 students and two teachers while barricaded inside.

Officials admitted on Friday that nearly 20 officers stood in a hallway outside of the classrooms during the attack, believing any potential victims inside were already dead.

‘Of course it was not the right decision. It was the wrong decision,’ Texas Department of Public Safety Director Steven McCraw said at a news conference.

The on-site commander ‘was convinced at the time that there was no more threat to the children and that the subject was barricaded and that they had time to organize’ to get into the classroom, McCraw said.

McCraw said there was a barrage of gunfire shortly after Ramos entered the classroom where they killed Ramos but that shots were ‘sporadic’ for much of the 48 minutes while officers waited outside the hallway.

He said investigators do not know whether or how many children died during those 48 minutes.

Ramos entered the classroom and locked the door at 11.34am. In the first few minutes, he fired more than 100 shots inside classrooms 111 and 112.

He carried on shooting ‘sporadically’ until 12.21pm, and it wasn’t until 12.50pm that police eventually gained access to the classrooms with a key from the janitor.

Throughout the attack, teachers and children repeatedly called 911 asking for help, including a girl who pleaded: ‘Please send the police now,’ McCraw said.

‘With the benefit of hindsight, from where I am sitting now – of course it was not the right decision. It was the wrong decision. There is no excuse,’ McCraw said.

He latter sobbed as he said he and other police officers ‘take an oath to protect people’ but failed.

‘We want to know why this happened and know if we can do better next time,’ he said.

Scores of Border Patrol agents also rushed to the scene after hearing the incident unfold on scanners. When they arrived, the Uvalde Police Department also told them not to go inside, according to a law enforcement official who spoke anonymously to The New York Times.

Eventually, the agents joined parents and a handful of local police officers in pulling kids through windows from other classrooms.

The agents did not understand why they were being told not to go inside when the gunman was still in the building.

Experts have slammed the decision to wait for back up as ‘outdated’ and ‘disgusting’.

‘Waiting an hour is disgusting. If that turns out to be true, then it is a disgusting fact,’ Sean Burke, a retired school resource officer from Massachusetts who now is the president of the School Safety Advocacy Council, told NBC.

Texas cops said last night that they didn’t immediately rush in to find the shooter on Tuesday’s attack after being shot at because they feared they might be killed, and even suggested that they deliberately locked the gunman in the classroom where he slaughtered 21 people in order to trap him.

This is how the shooting played out over the course of nearly two hours from when Ramos killed his grandmother at home. He arrived at the school at 11.28am and the first 911 calls were made. He then walked unobstructed into the building with his AR-15 and headed towards the classroom. He fought off cops at 11.44am, then was left alone in the room with the victims until around 12.44pm – when SWAT arrived. The incident was declared over at 1.06pm

Department of Safety Lt. Chris Olivarez made the astonishing comments during an appearance on CNN last night.

He was being challenged by Wolf Blitzer over why the first officers who responded to the shooting retreated after Salvador Ramos shot at them with his AR-15 and then waited an hour for tactical SWAT teams to take him out, leaving him alone in a classroom with the 19 fourth graders and two teachers who he slaughtered.

‘Don’t current best practices, Lieutenant, call for officers to disable a shooter as quickly as possible, regardless of how many officers are actually on site?’ Blitzer asked.

He replied: ‘In the active shooter situation, you want to stop the killing, you want to preserve life. But also one thing that, of course, the American people need to understand is that officers are making entry into this building. They do not know where the gunman is. They are hearing gunshots. They are receiving gunshots.’

He then appeared to try to take credit for the gunman being locked in the classroom with the kids for an hour – including some he shot at the start of the rampage who later died in the hospital – claiming it saved other lives.

Police initially said that the gunman barricaded himself inside the classroom and that they had trouble gaining access to the room, and one unnamed law official anonymously spoke out to say SWAT teams had to wait for a different school staff member to bring them a key to the class.

‘At that point, if they proceeded any further not knowing where the suspect was at, they could’ve been shot, they could’ve been killed, and at that point that gunman would have had an opportunity to kill other people inside that school.

‘So they were able to contain that gunman inside that classroom so that he was not able to go to any other portions of the school to commit any other killings,’ Lt. Olivarez said.