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 Jakobs 16 December 1942. Jakobs was taken to Ramsey Police Station before being transferred to Cannon Row Police Station in London, where he gave a voluntary statement to Major T.A. Robertson of MI5. Due to the poor condition of his ankle, Jakobs was transferred to Brixton Prison Infirmary for the night. The following day he was briefly interrogated by Lieutenant Colonel Stephens of MI5 at Camp 020 before being transferred to Dulwich Hospital where he remained for the next two months. Jakobs' court martial took place in front of a military tribunal at the Duke of York's Headquarters in Chelsea, London