Washington, D.C., interim Police Chief Jeffery Carroll announced at a press conference Tuesday that 13 officers have been placed on administrative leave in connection with an internal investigation into how the Metropolitan Police Department records crime statistics. The investigation began earlier this year after a referral from the U.S. Attorney’s Office, and Carroll said it was based on allegations of misconduct whose details he would not describe. “What I can tell you is there were allegations of misconduct that were made, and based on those allegations, members were investigated, and the outcome is related to these individuals,” Carroll said.

The department’s crime statistics collection has faced widespread scrutiny over the past year, after President Donald Trump issued a monthlong emergency order last summer that federalized the police force and launched a federal law enforcement operation in the nation’s capital. Trump has continuously pointed to the subsequent drop in crime as evidence that the surge made Washington, D.C., the safest city in the country. Mayor Muriel Bowser and other city officials, however, have maintained that crime was already trending downward before the federal intervention.

A report released in December by the Republican-led House Committee on Oversight and Government Reform concluded that then-Chief Pamela Smith often threatened, punished and retaliated against police commanders who presented her with “spikes in crime.” The committee found that the police chief pressured subordinates to manipulate department data to artificially lower the city’s crime rates. Separately, an investigation by U.S. Attorney Jeanine Pirro’s office determined that a significant number of MPD reports had been misclassified to make crime rates appear lower than they are. Neither investigation resulted in criminal charges. Pirro said at the time it was up to the MPD to take steps to address “these underlying issues.”

Carroll, who took over as interim chief in December, said Tuesday that the officers placed on leave have not been fired and are entitled to an administrative process, including a possible hearing before a panel of high-ranking officers who would assess the evidence and recommend discipline. “The administrative process must be allowed to take its course, and that process is outlined in our MPD general orders,” he said. He added that the department is conducting assessments and training for officers on how to submit crime data, but he declined to release the internal investigation publicly. “We use crime statistics every day to help us with deployment across the city. I do have confidence in those numbers,” he said.

House oversight committee chairman James Comer said in a statement that the department’s personnel action was “a step in the right direction,” but he added that it only confirmed the work of his committee. Comer said he expected to receive the MPD’s internal report and all related documents to “ensure crime data is reported accurately and that anyone responsible for manipulation is held accountable.” Bowser has separately called for an independent investigation by the city’s inspector general, which began in January.