KGB was the Soviet counterpart to CIA and FBI. "KGB" ("КГБ") is an abbreviation for "State Security Committee" but over the time, it became associated if not synonymous with the "empire of evil", the USSR. After the fall of the Soviet Union, KGB was officially succeeded by FSB.
KGB is target of many conspiracy theories, mostly regarding overthrow of US-friendly governments and installing Soviet satellite states. Furthermore, some believe that KGB never ceased to exist but has instead gone underground and is currently ruling Russia (with the ex-President and current Prime Minister Vladimir Putin admittedly being a former KGB agent).
They may have also had their hand in the Kennedy Assassination.
- KGB. Wikipedia.