Complex sentence: As the head of security Bischoff established the front company Mittelwerk GmbH used to conceal the missile production facility's true purpose from the Allies and was also charged with preventing organized attempts by the prisoner-laborers to sabotage the V-weapons during the assembly process.
Split into simpler sentences: As the head of security Bischoff established the front company of Mittelwerk GmbH; used to conceal the missile production facility's true purpose from the Allies. He was also charged with preventing organized attempts by the prisoner-laborers to sabotage the V-weapons during the assembly process.