When the German forces invaded the Soviet state in June 1941, José Díaz was forced to take refuge in Pushkin. In autumn, he settled in Tbilisi (Georgian SSR) but his ailment and the immense pain it caused him to take his own life that spring. The circumstances of his death have been disputed ever since, with many believing that he had actually been murdered on Stalin's orders. Notably, the stance Díaz had taken in 1939, when he asked for the PCE to be given full control over the Republican government, went clearly (albeit perhaps unwittingly) against the Stalinist strategy.