Complex sentence: The man that he killed was Rodger Prescott, a forger from Chicago whose description matches that of a Mr. Waldron, the former occupant of Nathan Garrideb's current address some six years ago.
Split into simpler sentences: The man that he killed was Rodger Prescott, a forger from Chicago, and his description happens to match Mr. Waldron's. He was the occupant of Nathan Garrideb's current address some six years ago.