George Trofimoff is a retired U.S. Army Reserve colonel who was arrested June 2000 on the count of spying for Russia for over 25 years. He provided classified information to Russia from 1959-1994, while working a civilian job after retiring from the military. It is believed he turned over more than 50,000 documents to the Russians. Trofimoff, who is the highest ranking U.S. officer ever accused of spying, was convicted of espionage and sentenced to life in prison in 2001.
(From: https://www.dhra.mil/PERSEREC/Espionage-Cases/army2/)
Historical Dictionary of Russian and Soviet Intelligence by 
