Todor Zhivkov to 1988, Bulgaria won an unprecedented 153 Olympic medals and numerous European and world competitions in sports as diverse as volleyball, rhythmic gymnastics and wrestling. Dissent was punished under Zhivkov's rule. The CSS was a feared tool of control, and overt opposition largely stayed underground until the late 1980s. In 1978, the Bulgarian dissident Georgi Markov was assassinated in London by an agent who stabbed him with an umbrella tip which implanted a very small ricin ball. According to former KGB general Oleg Kalugin, this was requested by Zhivkov and either performed by the KGB or it assisted the CSS;
Assassination assassinated by ricin poisoning. A tiny pellet containing the poison was injected into his leg through a specially designed umbrella. Widespread allegations involving the Bulgarian government and KGB have not led to any legal results. However, after the fall of the USSR, it was learned that the KGB had developed an umbrella that could inject ricin pellets into a victim, and two former KGB agents who defected said the agency assisted in the murder. The CIA made several attempts to assassinate Fidel Castro, many of the schemes involving poisoning his cigars. In the late 1950s, KGB assassin Bohdan Stashynsky killed