Less than six months after a gunman opened fire on students and teachers inside Robb Elementary School in Uvalde, Texas, Lt. Mariano Pargas has resigned from the Uvalde Police Department.

Texas Mayor Don McLaughlin told CNN that Pargas resigned on Thursday (Nov. 17) and that it went into effect immediately. The mayor and Uvalde City Council were set to hold a special meeting on Saturday (Nov. 19) to discuss the possibility of terminating Pargas when he submitted his resignation.

The mass shooting unfolded at Robb Elementary on May 24. In total, 19 students — ranging from ages 9 to 11 — and two teachers were killed.

The veteran officer was with the Uvalde Police Department for 18 years. He was in command of the agency when over 400 officers gathered outside the elementary school. In July, the Texas House Committee released a report determining Pargas was one of the first to arrive on the scene.

As previously reported by REVOLT, the first calls of an armed man being at the school came in around 11:30 a.m. Within a minute of the call, the gunman, identified as 18-year-old Salvador Ramos, began firing shots. By 11:33 a.m., he entered the school and fired upwards of 100 rounds into two classrooms. By the time officers confronted Ramos, the attack had been underway for an hour.

“The officers had weapons, the children had none. The officers had body armor, but the children had none. The officers had training, the subject had none,” Steve McCraw, director of the Texas Department of Public Safety, told NPR in June. The school’s failed safety procedures and agency protocols were each cited as contributing factors to the death toll.

According to Texas Tribune reports, School District Police Chief Pete Arredondo was fired on Aug. 24, and Superintendent Hal Harrell retired in October after facing months of criticism over the district’s school safety policies.