Person in Frederick Co. impersonating law enforcement, sheriff's office says The Frederick County Sheriff's Office was alerted of the wanna-be law enforcement person after receiving numerous calls in March and April. Police lights generic, file photo. Author: Khalida Volou (WUSA9) Updated: 7:49 AM EDT April 15, 2021 FREDERICK COUNTY, Md. — A police impersonator in the Frederick County area has been making illegal traffic stops for the past two months, Frederick County Sheriff's Office (FCSO) said. FCSO was alerted of the wanna-be law enforcement person after receiving numerous calls in March and April. They said in a recent encounter on April 11 around 6 p.m., the cop impersonator conducted a traffic stop in a black SUV with a single blue LED light bar.