The former wife of a retired Navy communications specialist charged with running a spy ring involving his son and brother said in an interview published Wednesday, "I did what I believed in" by tipping the FBI about the operation.

As John A. Walker Jr. and his son, Michael, pleaded innocent Tuesday in Baltimore to espionage charges, Barbara Joy Crowley Walker said that she and her daughter, Laura Walker Snyder, went to authorities in Boston several months ago.

John Walker, 47, is charged with masterminding a spy ring the FBI says sold secrets to the Soviet Union for at least 20 years. The FBI alleges Walker tried to recruit Snyder, an Army communications specialist from 1978 to 1979. Snyder has not been charged.