The school district in Uvalde, Texas, suspended its entire police force on Friday, pending the outcome of a probe following the mass shooting in May that killed 19 students and two teachers, the district said in a statement.

The district said it suspended all activities of the Uvalde Consolidated Independent School District Police Department “for a period of time.” The police force consisted of five officers and one security guard, according to its website.

The district is awaiting the results of an investigation led by the Texas Police Chiefs Association and an outside firm into the shooting at Robb Elementary School, expected to be released later this month.

The district said it made the decision to suspend the police force because “recent developments have uncovered additional concerns with department operations.”

The district also said that as a “result of the recent developments,” one officer, Lieutenant Miguel Hernandez, was placed on administrative leave. Ken Mueller, the director of student services, was also placed on administrative leave and will retire, the district said in its statement.

The school district declined to provide more information about the suspension and the state of department operations. The police department was not available for comment.

The police department has been under investigation for its response to the shooting in May, including delays by officers in reaching the gunman while he was holed up in a classroom.

The school district said it requested additional officers from the Texas Department of Public Safety to provide campus security.

•PHOTO FILE- A police officer is seen in front of a makeshift memorial at Robb Elementary School in Uvalde, Texas, May 29, 2022.