Complex sentence: Ritzi, the showgirl who had dined with him the evening he vanished, went missing from New York in August or September 1930, she was found in late September 1930, living in Youngstown, Ohio with her parents.
Split into simpler sentences: Ritzi, the showgirl who had dined with him the evening he vanished, went missing from New York in August or September 1930. She was found in late September 1930, living in Youngstown, Ohio with her parents.