Ricin the attack on Georgi Markov another Bulgarian defector, Vladimir Kostov, survived a similar attack. Kostov was standing on an escalator of the Paris metro when he felt a sting in his lower back above the belt of his trousers. He developed a fever, but recovered. After Markov's death the wound on Kostov's back was examined and a ricin-laced pellet identical to the one used against Markov was removed. Several terrorists and terrorist groups have experimented with ricin and caused several incidents of the poisons being mailed to U.S. politicians. For example, on May 29, 2013 two anonymous letters sent to
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