Since mid-May, Josef had been involved in a cross-ruff with fellow spy Karel Richter; one spy being played off the other. MI5, however, was eager to move in the direction of prosecution and by mid-June, felt that they had all of their ducks in a row. All that was required was for Lt. Col. Hinchley-Cooke to take a statement from Josef.
For this purpose, Inspector Douglas Grant from Special Branch (Metropolitan Police) transported Josef from Latchmere House to Cannon Row Police Station. The statement was taken in the presence of Inspector Grant, Detective Sergeant Smith and Detective Constable Wills. Hinchley-Cooke took the statement in the form of question and answer. After covering the basics of Josef's birth, nationality and military service, Hinchley-Cooke briefly touched on how Josef had arrived in England (by parachute from a German military aircraft) and his purpose in coming to England.
This statement would be used at the court-martial against Josef.