Texas police missed 10 opportunities to stop a school shooter who killed 21 people and wrongly told parents their murdered children were alive, officials said on Thursday.

The Department of Justice report into the 2022 Uvalde shooting was heavily critical of officers, declaring their response to the incident a series of “cascading failures”.

The DOJ was commissioned to investigate the shooting just days after 18-year-old Salvador Ramos killed 19 students and two teachers at Robb Elementary School in Uvalde, southern Texas.

Police waited over an hour before storming the classroom where he had held students and teachers, the report said, singling out the school police commander Pete Arredondo for failing to act quickly enough.

Part of the delay was caused by officers spending 40 minutes searching for a key to a shared classroom space that they believed to be locked, even though it had been open.

CCTV footage from the school showed one officer stopping to check his phone while another applied hand sanitiser as armed police waited in the corridor.

Ramos was eventually shot dead roughly 77 minutes after police arrived on the scene, when a tactical team entered the classroom he was in and took him down.

‘Failed leadership, training and policy’

The critical incident review said the most “significant failure” was that officers should have “immediately recognised the incident as an active shooter situation”, rather than waiting to intervene.

Merrick Garland, the US attorney general, on Thursday visited the city’s 21 murals to those killed in the shooting.

“As a consequence of failed leadership, training, and policies, 33 students and three of their teachers — many of whom had been shot — were trapped in a room with an active shooter for over an hour as law enforcement officials remained outside,” he said after briefing family members on the DOJ’s findings.

“I told the families gathered last night what I hope is clear among the hundreds of pages and thousands of details in this report: Their loved ones deserved better,” Mr Garland added.

The report said police had informed some parents that their children were alive, although they had already been killed.

One family member told the inquiry they had asked staff at the local hospital where their child had been taken, and was told they were not in the building. It later transpired the child was dead and had been at the hospital for hours, the report said.