On April 11, 1943, the first news about the crime committed in the forest near Katyn was released to the world.

On 4 July 1943, at 23:07, moments after take-off from Gibraltar Airport, Liberator II aircraft AL523 with General Władysław Sikorski on board, crashed into the Mediterranean Sea.

Father Jan Cieplak was auxiliary bishop of the Mogilev archdiocese, at that time the largest Roman Catholic archdiocese in the world, covering the whole of Russia up to Sakhalin.