Pete Arredondo has been blamed for the botched response to the attack which saw 19 children killed.
A police chief accused of botching the response to the fatal shooting of 19 school children and two teachers in Uvalde, Texas, has been put on leave.
Pedro “Pete” Arredondo, head of the school district police force, has been blamed for law enforcement delays in confronting the gunman.
Defending his actions, the 50-year-old has said he did not think he was the official in charge at the time.
Public anger has risen as more details of the 24 May attack emerge.
State lawmakers are investigating why police waited for more than an hour outside the Robb Elementary School classroom in which the assailant had barricaded himself before a team made entry.
School district superintendent Hal Harrell said on Wednesday he had placed Mr Arredondo on administrative leave effective immediately, citing “the lack of clarity that remains and the unknown timing of when I will receive the results of the investigations”.
He said he had originally planned to “wait until the investigation was complete before making personnel decisions”, but was “still without details” of what the inquiry has found.
Mr Arredondo has not spoken in a public capacity since last month’s shooting.
In an interview with the Texas Tribune earlier this month, however, he said he “took on the role of a front-line responder” during the attack and assumed another official had taken control of the broader response.
He said officers on the scene could not find a key to unlock the door to the classroom until 77 minutes after the attack started.
But Texas public safety chief Steven McCraw said on Tuesday the door was not locked and there was no evidence officers tried to open it.
Mr McCraw testified to a state Senate hearing that there were enough police on the scene to have stopped the gunman three minutes after he entered the building.
Labelling the response an “abject failure”, Mr McCraw also said Mr Arredondo had “decided to place the lives of officers before the lives of children”.
Also on Tuesday, Uvalde Mayor Don McLaughlin accused state authorities of selectively releasing information about the shooting to scapegoat local law enforcement and deflect scrutiny from the state’s response to the attack.
The decision to remove Mr Arredondo as police chief comes amid uncertainty over his future on the Uvalde city council.
Newly elected to the council last month, and sworn in one week after the massacre at Robb Elementary, he is yet to attend a council meeting and had requested a leave of absence.
But the council unanimously denied his request at its Tuesday meeting after angry residents opposed the move, some calling for his firing.
“Please, please, we’re begging you, get this man out of our lives,” Berlinda Arreola, the grandmother of murdered 10-year-old Amerie Jo Garza, said.