Horáková stood up against the single-party communist rule in Czechoslovakia, and became the subject of a show trial where she was accused of espionage and treason. On June 8, 1950, she was sentenced to death along with lawyer Oldřich Pecl, state security staff guard Jan Buchal, and journalist Závis Kalandra. They were all executed on June 27, 1950, in Pankrác prison in Prague.