The Texas Department of Public Safety (DPS) has announced that it will investigate the actions of state police officers during the Uvalde Elementary School massacre.
The agency said in a statement on Monday that the investigation would determine whether "any violation of policy, law or principle has occurred" during the May 24 mass shooting at Robb Elementary School in which 19 children and two teachers were killed.
It is the first time the Texas DPS has said it will investigate the actions of its own officers in the two months since the deadliest school shooting in Texas history.
The announcement came a day after an investigative committee of the Texas House of Representatives released a report detailing the "systemic failures" of law enforcement officers to respond to the attack.
The 77-page report said 376 officers - including more than 90 state soldiers - arrived at the school in a chaotic scene marked by a lack of clear leadership and substantial urgency.
The attack in Uvalde was one of the deadliest school shootings in the United States in years and has fueled a renewed debate over gun control and the effectiveness of police.
A teacher who was shot and bloodied in her classroom as her students were shot, standing idly in the hallway with police, said he would "never forgive" respondents.
The children called 911 several times begging someone to save them, but it took more than 70 minutes for law enforcement to break into the room and shoot the gunman.
Following Uvalde, the US Congress passed substantial gun reform legislation for the first time in decades, although critics have said it does not go far enough.