21 August 1940,
Catalan Ramón Mercader murdered León Trotski playing with a piolet in Mexico City. After the death of Lenin and the loss of the power struggle against Stalin, Trotski, leader of the Red Army, was first expelled from the party and after the Soviet Union in 1929. He spent his whole life in exile. From Mexico he tried to write against Stalinism and organize his followers. After surviving numerous attempts to attack him, he was killed by Mercadona, Soviet secret agent NKVD, on behalf of Stalin.
Source:
Josep Fontana, The Century of Revolution. Munduko history bat 1914etik. (Ed. Criticism)