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;
Bulgarian umbrella Vladimir Kostov the same year in the Paris "Métro". The poison used in both cases was ricin. Both assassination attempts are believed to have been organized by the Bulgarian Secret Service of the time of the Cold War with the assistance of the KGB. Such an umbrella was intended to be used in the assassination of Pallo Jordan and Ronnie Kasrils by the South African Civil Cooperation Bureau death squad. These two cases inspired the 1980 French film "Le Coup du parapluie" ("The Umbrella Coup") directed by Gérard Oury and starring Pierre Richard, and Bulgarian writer Stefan Kisyov's novel "The