FILE - In this Monday, Oct. 28, 1985 file photo, John A. Walker Jr. is escorted by a federal marshal as he leaves the Montgomery County Detention Center in Rockville, Md. enroute to a federal court in Baltimore. The former U.S. Navy Warrant Officer convicted during the Cold War of leading a family spy ring for the Soviet Union has died in a prison hospital in North Carolina, officials said Friday, Aug. 29, 2014. (AP Photo/Bob Daugherty)