Three D.C. ambulances were “improperly out of service” earlier this month when Prince George’s County authorities had to transport an injured D.C. police officer to the hospital because the city didn’t have any units of its own available, an internal investigation has found.

“The three improperly out of service units all failed to properly follow protocol,” Deputy Mayor Paul Quander wrote in a report that said seven unidentified employees are facing “appropriate personnel action.”