Original: The thirty-seven-year history of the USSR KGB ended when its Chairman , Col.-Gen . Vladimir Kryuchkov , led the 19 -- 21 August 1991 Soviet coup d'état attempt to depose Soviet President Mikhail Gorbachev .
Simplified: The KGB was dissolved when its chief , Colonel-General Vladimir Kryuchkov , used the KGB 's resources in aid of the August 1991 coup attempt to overthrow Soviet President Mikhail Gorbachev .