Recruitment then emphasised mercenary agents, an approach especially successful[citation needed][quantify] in scientific and technical espionage, since private industry practised lax internal security, unlike the US Government. One notable KGB success occurred in 1967, with the walk-in recruitment of US Navy Chief Warrant Officer John Anthony Walker. Over eighteen years, Walker enabled Soviet Intelligence to decipher some one million US Navy messages, and track the US Navy.[12]
In the late Cold War, the KGB was successful with intelligence coups in the cases of the mercenary walk-in recruits FBI counterspy Robert Hanssen (1979–2001) and CIA Soviet Division officer Aldrich Ames (1985–1994).[13]