Complex sentence: After the war, the Fields' adopted daughter Erica had moved to the American Zone of occupied Germany and got a job with the OSS, later leaving to join the German communist party, and work as secretary to the communist representatives in the Hesse Regional Parliament.
Split into simpler sentences: After the war, the Fields' adopted daughter Erica moved to the American Zone of occupied Germany and got a job with the OSS. She left to join the German communist party and worked as secretary to the communist representatives in the Hesse Regional Parliament.