(NewsNation) — On the day when Uvalde students went back to class for the first time since 21 people died in a massacre at their school, several officers have been referred to a state watchdog for possible discipline.

The Office of the Inspector General will investigate five responding officers, the state’s public safety department confirmed to NewsNation. They did not provide any names, but did note two are on paid leave.

The law enforcement response has been under scrutiny since the hours after the community and country learned what happened on the morning of May 24 at Robb Elementary School. Nineteen students and two adults died as a shooter entered two classrooms before barricading himself.

In the days after the attack, police claimed a locked door prevented them from entering, but subsequent investigation found that door was open. All told the shooter was in a classroom for almost an hour while police stood outside.

There were no survivors in the classroom, but critics say law enforcement might have been able to get victims to hospitals sooner if they’d entered the room quicker.

After the shooting, police leaders said the situation was treated like a barricaded subject instead of an active shooter. In July, a memo went out emphasizing that all school shootings should be treated as active threats.

“DPS Officers responding to an active shooter at a school will be authorized to overcome any delay to neutralizing an attacker. When a subject fires a weapon at a school he remains an active shooter until he is neutralized and is not to be treated as a ‘barricaded subject,’ Texas Department of Public Safety Director Steven McCraw wrote in a memo to his staff in July.

For the students’ first day back Tuesday, 30 state officers patrolled the district’s buildings.

Former Uvalde School police Chief Pete Arredondo has faced calls for accountability after his lawyer defended the police’s response in a scathing letter to the school board on the evening they fired him. The lawyer argued Arredondo was entitled to due process as a public employee, but the school board terminated his employment anyway.

Arredondo was elected to Uvalde’s City Council before the shooting, but resigned in July after being sworn in during a secret proceeding.

State Sen. Roland Gutierrez, who represents Uvalde’s district, criticized the state’s transparency in a statement Tuesday.

“We cannot stop here. True justice requires transparency, accountability, and a commitment to solutions. Greg Abbott and DPS need to fess up and take action to stop the plague of gun violence in our communities,” he wrote.