MOSCOW, August 30 (RIA Novosti) - Former US Navy officer John A. Walker Jr., who was given two life sentences for engaging in espionage during the Cold War, died in a US federal prison on Friday, CNN reports.
The information he passed along to the Soviet Union facilitated "access to weapons and sensor data and naval tactics, terrorist threats, and surface, submarine, and airborne training, readiness and tactics," the late former U.S. Secretary of Defense Caspar Weinberger wrote in a statement that was released by CNN.
Walker controlled a spy ring that included his son, his brother and one of his friends. The espionage continued from 1968 to 1985, when he was turned in by his ex-wife and apprehended by the FBI.
US authorities announced that Walker had sold the Soviet Union secret codes, giving it access to ciphered Navy messages and allowing it to observe US military bases. The former Navy officer is estimated to have earned more than $1 million for the secret data. According to the US government, Walker's activity caused serious damage to national security, CNN reports.
Walker was 77 years old when he died. The cause of his death remains unknown, but according to previous reports, he had been suffering from throat cancer.