The US justice department has said it will review the law enforcement response to the shooting in Uvalde, Texas, that left 19 students and two teachers dead.
The review comes amid mounting pressure and questions about the shifting and at times contradictory information about what happened in the shooting last Tuesday at Robb Elementary School and how police responded.
Justice department spokesman Anthony Coley said the review would be conducted in a fair, impartial and independent manner and that the findings would be made public.
The announcement came as US president Joe Biden was visiting Uvalde, where he and first lady Jill Biden paid their respects at a memorial.
The goal of the review, which the mayor requested, is “to provide an independent account of law enforcement actions and response that day, and to identify lessons learned and best practices to help first responders prepare for and respond to active shooter events,” Mr Coley said in a statement.
Handling the review is the department’s Office of Community Oriented Policing Services.
It was not immediately clear how the review would be conducted, whether law enforcement officials could be compelled to cooperate in the review and when it might be completed.
Such a review is somewhat rare and most after-action reports that come after a mass shooting are generally compiled by local law enforcement agencies or outside groups.