Texas officials have agreed to make public video footage from inside Uvalde’s Robb elementary school during the deadly mass shooting there, an official said on Monday, though the district attorney in the local county is being accused of blocking the video’s release.

State representative Dustin Burrows, the chairperson of a special legislative committee investigating the shooting, said Texas’ department of public safety had agreed to release surveillance footage from inside the hallway at the school.

“This video would be of the hallway footage from Robb elementary school – it would contain no graphic images or depictions of violence,” Burrows said.

The video would “begin after the shooter enters the room, and end before a breach of that room”, giving stark insight into what officers did for more than an hour before confronting the gunman that day.

An 18-year-old man fleeing the scene of another shooting killed 19 children and two teachers inside a classroom on 24 May. It took 77 minutes from the first 911 call reporting the shooter’s arrival at the campus for law enforcement officers to kill the gunman, spending much of that time in a hallway outside the classroom where the killings occurred.

Elected officials have pushed for surveillance footage from the hallway to be made public as part of their investigation into the response to the shooting.

Burrows had previously said publication of the footage was dependent on agreement from the state public safety department, but on Friday an official with that agency said the Uvalde district attorney, Christina Mitchell Busbee, was responsible for the delay.

“We do not believe [the video’s] public release would harm our investigative efforts,” the public safety department’s deputy director of homeland security operations, Martin Freeman, wrote in a letter to Burrows. “In fact, releasing this video would assist us in providing as much transparency as possible to the public.

“However, we have communicated your request to Uvalde County district attorney Christina Mitchell Busbee. She has objected to releasing the video and has instructed us not to do so.”

A group of Texas legislators has since written to Busbee requesting the release of the video. It is unclear if they have received a response. Busbee’s office did not immediately respond to a request for comment from the Guardian.

In Monday’s hearing, Burrows said the committee investigating the shooting would look to publish a report “sooner than later: so that people can start getting some information and seeing what it is that we are discovering”.

The video, if released, would be an important part of that report, Burrows said.

“I can tell people all day long what it is I saw, the committee can tell people all day long what we saw, but it’s very different to see it for yourself,” he said.

“And we think that’s very important and we will continue to put pressure on the situation and consider all options in making sure that video gets out for the public to view.”