DALLAS — A lieutenant who was the acting chief of the police in Uvalde, Texas, during the shooting at Robb Elementary School stepped down on Thursday, a city spokeswoman said, amid questions about his actions and after the release of video footage showing that he did not order officers to quickly breach the classrooms.
The lieutenant, Mariano Pargas Jr., was in charge of the Uvalde Police Department while its chief was on vacation when a gunman opened fire inside the school, killing 19 children and two teachers. Mr. Pargas was placed on administrative leave over the summer, and the Uvalde City Council had been expected to discuss his possible termination on Saturday in a special meeting.
“Lt. Pargas retired effectively immediately,” Gina Eisenberg, the spokeswoman, said in an email. “He was eligible to retire. Pargas served the city of Uvalde for 18 years.”
Mr. Pargas was among the first officers to enter the school on May 24 after a gunman began firing inside a pair of connected classrooms.
But video from surveillance and police body cameras showed that despite being in charge of the city’s police at the time, Mr. Pargas quietly waited and did not attempt to organize officers to re-engage with the gunman after he fired at officers and caused them to retreat from the classroom doors.
It would take more than an hour before officers from the Border Patrol entered the classrooms and confronted the gunman, killing him.
Mr. Pargas told a Texas State House investigatory committee that he believed that Pete Arredondo, the chief of the Uvalde school district police, had jurisdiction over the incident and had been coordinating the response, which eventually grew to include hundreds of officers from more than a dozen agencies.
The committee faulted Mr. Pargas, in addition to Mr. Arredondo, for not coordinating with other agencies. After the vacationing police chief, Daniel Rodriguez, called Mr. Pargas and told him to set up a command post, Mr. Pargas attempted to do so in a funeral home across from the school. “This did not result in the establishment of an effective command post,” the committee said in its July report.
The committee found that Mr. Pargas was present, early in the standoff, when a Uvalde school officer, Ruben Ruiz, informed the officers inside the school that his wife was among those shot but was still alive in the classrooms. “She says she is shot,” Officer Ruiz told them, according to the committee’s report. (Mr. Ruiz had communicated with his wife, Eva Mireles, by phone, The New York Times reported in June. She later died from her wounds.)
Footage published by CNN on Monday showed that Mr. Pargas also later learned of a 911 call placed by a child who was inside one of the classrooms who told police dispatchers that several children remained alive inside with the gunman.
Mr. Pargas did not immediately respond to a request for comment. In the committee’s report, he said he had been waiting for personnel who had better equipment, like shields.
With his resignation on Thursday, Mr. Pargas joined a growing list of officers who have lost their jobs over the law enforcement response to the shooting, which the head of the state police, Steven McCraw, has called an “abject failure.”
Mr. Arredondo was fired over the summer. In the aftermath of the shooting, he was blamed for the delayed response by Mr. McCraw, who said Mr. Arredondo had been the incident commander during the shooting. Mr. Arredondo said he did not see himself in that role.
But over the summer, Mr. McCraw’s agency, the Department of Public Safety, began investigating the actions of several of its own officers.
Last month, the department issued termination papers to one of the officers, Sgt. Juan Maldonado, who along with Mr. Pargas was among the first to arrive at the school. On body camera video, Mr. Maldonado could be seen staying in a doorway to the school rather than moving toward the gunfire inside.
The internal investigation by the Department of Public Safety is continuing into at least six other officers including a D.P.S. trooper, Crimson Elizondo, who also remained outside as officers entered the school minutes after the shooting began.
Ms. Elizondo left the state police over the summer for a job with the Uvalde School District Police Department. After some parents objected, the school district fired her.
Mr. Maldonado and Ms. Elizondo have not responded to requests for comment.
In addition to his role with the police department, Mr. Pargas is also a county commissioner in Uvalde and was re-elected as a Democrat to the position this month.
He prevailed in the election despite facing write-in challenges, including from Javier Cazares, whose 9-year-old daughter, Jackie, died in the elementary school shooting.