Complex sentence: In August 1942, they both took in the Communist Albert Hößler (or Hössler), who since the 1930s had lived in the Soviet Union and had now parachuted into Germany to help the resistance group convey information to the Soviet Union.
Split into simpler sentences: In August 1942, they took in the Communist Albert Hößler (or Hössler), who had lived in the Soviet Union since the 1930s. He had parachuted into Germany to help the resistance group convey information to the Soviet Union.