Following the May massacre in Uvalde, Texas, a simple account of the police response took hold: Following his command, scores of officers from over a dozen federal, state, and local agencies stood by idly, waiting for equipment and SWAT teams while children trapped in classrooms with the gunman dialed 911 for assistance.

The Texas Department of Public Safety, which is leading the criminal investigation into the mass shooting, described this shocking scene.

D.P.S. continues to claim that the evidence supports this version of events and the public understanding it fueled nearly five months later, despite questions raised by other government reviews and journalists.

However, The New York Times’ analysis of the footage revealed significant gaps and contradictions in the D.P.S. findings.

While visual evidence from the scene is limited, it suggests that the problem was more than just one inept school police chief or officers who knew better but did nothing. High-ranking officers, experienced state troopers, police academy instructors, and even federal SWAT specialists arrived at the same conclusions and were detoured by the same delays that the school police chief has been blamed for.

Three days after the shooting, D.P.S. Director Steven McCraw announced that his investigation had determined why it took the police 77 minutes to kill the gunman. Mr. McCraw stated that all officers were trained to respond immediately to active shooters, but they were hampered when the incident commander, Pete Arredondo, incorrectly determined the gunman was a “barricaded subject,” which requires a slower, more deliberate response.

However, Mr. McCraw’s claims that Mr. Arredondo stymied 360 officers with flawed orders or misinformation are not supported by the available footage, which shows little evidence that commands were issued, let alone widely communicated, by the school chief.

The available video evidence shows that the D.P.S. timeline — which Mr. McCraw told lawmakers was supported by “frame-by-frame” video analysis — miscast Mr. Arredondo’s role and omitted actions and inaction by other officers, particularly D.P.S. troopers and federal agents, who were involved earlier or more centrally than it notes.

BORTAC, the Border Patrol’s elite tactical agents, took command about halfway through the response and discovered immediately that children were trapped inside with the gunman. However, it took BORTAC 37 minutes to breach the classrooms after planning, testing keys, and preparing equipment.

The Times examined body camera footage from seven Uvalde Police Department officers as well as a compilation of security-camera feeds first published by The Austin American-Statesman. The D.P.S. has refused to release evidence from its investigation, including radio communications and more than 30 body cameras. The New York Times is a member of a media coalition suing the D.P.S. over public records requests.

Mr. Arredondo has been blamed by multiple media outlets and a Texas House investigative committee. In September, D.P.S. admitted to revising its protocol for active shooter incidents and said the inspector general was looking into seven employees.

The US Border Patrol and the Uvalde Police Department both declined to comment, citing internal investigations. The Uvalde County constables and the Uvalde school district did not respond to The Times’ inquiries. The district announced an internal investigation and suspended its police force recently.

Mr. Arredondo refused to comment for this article. Before being fired in August, he admitted that he thought the gunman was “barricaded,” but claimed that because the “crime spree” began outside the school district’s jurisdiction, he was only a front-line responder and not incident commander.

Mr. Arredondo was designated to take command by the school’s active shooter plan, which he wrote, and footage shows some officers referring to him as “in charge,” but there’s little visual evidence he directed the response or even stayed abreast of key developments from the position he took during the incident.

Whatever errors Mr. Arredondo made, the footage shows that the D.P.S. findings are selective, often imprecise, and fail to explain how a chief who failed to establish command could compel hundreds of trained officers, many of whom had family members at the school, to disregard long-established policing protocol with almost no discernible dissent. The Times discovered inconsistencies during three stages of the police response.