The Baltimore Police Department took 120 patrol cars out of service last week after a woman reported that she had been assaulted by a person wearing a police uniform inside of a patrol vehicle, Police Commissioner Michael Harrison explained during a press conference on June 11.

Baltimore PD investigators pulled 120 patrol cars out of service and talked to neighboring police agencies who may have patrol cars that also fit the description. Detectives also inspected more than 300 body cameras and 600 written activity logs, and collected license plate data from any vehicles in the area when the incident occured.

After several days of investigation, the Police Department arrested Richard Steven Barnes, a security guard at a local hospital who posed as a police officer.

While the vehicles were out of service, officers doubled up for patrol, with the department assigning two officers to each patrol car still on the roads for the duration of the investigation, the Baltimore Sun reported.