Ricin immunogenic in mice, rabbits, and humans. It has completed two successful clinical trials. Ricin has been involved in a number of incidents. In 1978, the Bulgarian dissident Georgi Markov was assassinated by Bulgarian secret police who surreptitiously shot him on a London street with a modified umbrella using compressed gas to fire a tiny pellet contaminated with ricin into his leg. He died in a hospital a few days later and his body was passed to a special poison branch of the British Ministry of Defence (MOD) that discovered the pellet during an autopsy. The prime suspects were the Bulgarian
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