A new Department of Justice report heavily criticized law enforcement's response to the May 2022 mass shooting at Robb Elementary School in Uvalde, Texas, explicitly calling it a "failure," Attorney General Merrick Garland said on Thursday.

Why it matters: The DOJ report said the state and local police who initially arrived at the school mishandled the situation, wasting precious time that could have been used to save lives.

• The gunman killed nineteen children and two adults, some of whom were shot while they were trapped inside classrooms with the shooter for over an hour.
• Local and state law enforcement agencies have faced ferocious criticism over their response to the deadliest school shooting in Texas history.

Details: Garland said the most significant mistake was the responding officer's failure to continue to treat the scene as an "active shooter scenario."

• The approach calls for immediate and continuous confrontation with a threat until it is eliminated.
• Garland said officers instead switched to a "barricaded subject scenario," erroneously believing they had time to reassess the situation and prepare for a confrontation with the gunman.
• The response was also marred by miscommunication, with local officers not made aware that victims inside the classroom with the shooter had made multiple 911 calls, according to public information available before the Justice Department's report.

The DOJ's report condemned local police commanders' inability to establish clear leadership and reduce disorganization and confusion.

• The failure contributed to the 77-minute delay before police finally breached a door to a classroom and killed the lone gunman. Over 370 police responded to the shooting.
• "Leadership in law enforcement is absolutely critical, especially in moments of dire challenge," the report states. "This leadership was absent for too long in the Robb Elementary School law enforcement response."

What they're saying: Garland stressed during a press conference Thursday that policing is difficult, especially when officers lack proper training.

• He said the responding officers deserved better training and leadership than they received, noting that some of them also lost family in the shooting.
• The attorney general said children in the U.S. "deserve better than to grow up in a country where an 18 year old has easy access to a weapon that belongs on the battlefield and not in the classroom."
• "Communities across the country and the law enforcement officers that protect them deserve better than to be forced to respond to one horrific mass shooting after another, but that is the terrible reality we face," he said.

The report also addressed a previous explanation police offered on why they did not confront the gunman sooner.

• Police said the locked doors to Rooms 111 and 112, where the shooter was, were the primary delay to their response. Law enforcement officials said they needed to find either a master key or breaching tool to gain entry to the classroom.
• The federal reviewers concluded that at least one of the doors was probably unlocked the entire time. They also concluded that no one tested the doorknobs, while also noting that several other doors inside the school were unlocked, per the report.
• It said the team of officers designated to enter the classrooms had assumed the doors were locked based on information they received from officers who were on the scene before them.
• A 2022 report from the Texas House of Representatives also concluded that there is reason to suspect that one of the doors were likely unlocked.

Some of the responding officers previously told investigators that the delay in confronting the gunman was also influenced by his weapon, an AR-15-style rifle, according to the Texas Tribune.

• The officers, some of whom were carrying similar weapons, said they didn't want to be killed by the "battle rifle."
• They said this factored into their decision to wait for the arrival of a Border Patrol tactical team equipped with protective armor and more training.

Associate Attorney General Vanita Gupta said there had also been a failure to treat victims within Rooms 111 and 112 after the shooter was killed.

• Gupta said plans to triage the 35 injured victims were not prepared during the delay.
• She said victims who had passed away were taken away from the school in ambulances, while children, some of whom had bullet wounds, were taken to hospitals on buses without medical attention.
• One adult victim was placed on the ground outside the school to be attended to before passing away from her injuries, Gupta noted.

Of note: The DOJ's report is not a part of a criminal investigation into the shooting but rather a "critical incident review" to provide an official account of how officials responded the shooting.

• It could help dispel deflections and disordered and conflicting accounts of the shooting that law enforcement agencies have publicly offered.

Go deeper: More training after botched Uvalde police response, but accountability still in question

Read the report:

Editor's note: This story was updated with information from the DOJ report.