The District is investigating whether rules governing the handling of employee documents have been broken after D.C. police and firefighters’ union leaders wrote a letter to the city’s inspector general saying firefighters found three dumpsters full of burning documents at the fire department’s training academy on Friday.

“Once this matter was brought to our attention, our Internal Affairs Division immediately began investigating,” read a short police statement released Wednesday.

“We are looking into whether any records retention protocols have been violated,” the statement said. “The Metropolitan Police Department will cooperate with the Office of the Inspector General during the course of their investigation.”

The letter says firefighters noticed that at least some of the documents were personnel records for members of the D.C. police department and fire and emergency medical services department. The letter says there were also unburned documents found in an abandoned car and scattered on the ground at the training facility.

This item has been updated.

Information reported by the Associated Press was used in this story.