Bulgaria–United States relations to work. Bulgaria became a member of the Warsaw Pact on May 14, 1955. Though no Soviet troops were stationed on Bulgarian soil, in 1968, Zhivkov sent a Bulgarian division to join Polish, Hungarian and Soviet troops to crush a popular uprising in Prague. In 1978, the Bulgarian secret police were implicated in the assassination in London of Georgi Markov, a Bulgarian dissident who was a correspondent for the BBC World Service, Deutsche Welle radio and the U.S. sponsored Radio Free Europe. Markov was assassinated with a poisoned umbrella on September 7, Zhivkov's birthday. The rise of democratic movements across
Umbrella man (JFK assassination) with a paralyzing agent at Kennedy to immobilize his muscles and make him a "sitting duck" for an assassination. After an appeal to the public by the United States House Select Committee on Assassinations (HSCA), Louie Steven Witt came forward in 1978 and claimed to be the "umbrella man". He claimed still to have the umbrella and did not know he had been the subject of controversy. He said that he brought the umbrella simply to heckle Kennedy whose father Joseph had been a supporter of the Nazi-appeasing British Prime Minister Neville Chamberlain. By waving a black umbrella, Chamberlain's trademark