AUSTIN, Texas (AP) — The head of Texas’ state police met again Monday with a committee investigating the Uvalde elementary school shooting as anger over why officers waited so long to confront the gunman mounts among families of the 21 people killed inside a fourth-grade classroom.

Nearly seven weeks after the deadliest school shooting in Texas history, a full account of the slow police response at Robb Elementary School remains incomplete and authorities at all levels have not released requests for public records, including for 911 recordings and body camera footage.

Hundreds of people, including relatives of some of the 19 children killed, gathered and marched in Uvalde under searing 100-degree (37.78 Celsius) heat during the weekend in a renewed push for answers and accountability.

State police and an investigative committee formed by the Texas House say they want to release a 77-minute surveillance video of the hallway where police, armed with rifles and bulletproof shields, gathered during the shooting but waited more than an hour before breaching the classroom. But state police insist they can’t because they don’t have authorization from the district attorney in Uvalde County.

The investigative committee wants to include the video in preliminary public findings that could be made public later this month. Rep. Dustin Burrows, a Republican who leads the committee, said Monday in a tweet that he planned to show the video to Uvalde residents “regardless of any agreement.”

Uvalde County District Attorney Christina Busbee has not responded to requests for comment about the video.

The committee says it has so far interviewed more than 40 people, including police who were on the scene. All the testimony has happened behind closed doors, which Burrows has said was necessary to elicit more candor from the witnesses.

Witnesses Monday included Uvalde County Sheriff Ruben Nolasco and Steve McCraw, director of the Texas Department of Public Safety, who has previously met with the committee and has publicly called the law enforcement response an “abject failure.”

Some Uvalde residents joined President Joe Biden on the White House lawn Monday as he showcased a new law meant to reduce gun violence. It is the most impactful firearms-violence measure Congress has approved since the 1994 enactment of a since-expired ban on semi-automatic guns that were defined as “assault weapons.” Yet gun control advocates — and even White House officials — say it’s premature to declare victory.

“I’m using this pain to speak to you today as a Uvaldian,” said Dr. Roy Guerrero, a pediatrician in Uvalde who treated some of the victims. “And to speak for the parents and victims who seek the truth, transparency, and ultimately, accountability.”