Josef Jakobs SW3, on 4–5 August 1941. The trial was held "in camera" because the German agent had been apprehended in a highly classified intelligence operation known as the Double Cross System. The British were aware that Jakobs was coming because his arrival information had been passed on to MI5 by the Welsh nationalist and "Abwehr" double agent Arthur Owens. After a two-day trial which involved hearing the testimony of eight witnesses, Jakobs was found guilty of spying and sentenced to death. Jakobs's execution took place at the miniature rifle range in the grounds of the Tower of London on 15 August
Josef Balabán that had been organized by former army officers. Beginning in the summer of 1939 he was one of the leaders of the organization. Together with Josef Mašín and Václav Morávek, Balabán was part of the group known as the Three Kings ("Tři králové"), which carried out intelligence gathering and sabotage. The group continued in communication with Paul Thümmel (agent A-54), a Nazi intelligence officer also working as a spy for Czechoslovakia. The most visible acts of sabotage were two bomb attacks carried out in Berlin: one in January 1941 against the Ministry of Air Travel ("Reichsluftfahrtministerium") and police headquarters, and