ST. LEONARD, Md. – On December 11 at 3:17 p.m., Trooper First Class Costello and Trooper Keyser stopped a vehicle on Rt. 4 in Prince Frederick for traffic violations.  John W. Proper, 64 of St. Leonard identified himself as a Maryland State Trooper.  He was unable to show MSP Credentials and through investigation it was determined that Proper was impersonating a police officer.  A search incident to the arrest revealed a loaded handgun was located in the vehicle.  Proper was arrested and incarcerated at the Calvert County Detention Center.