Complex sentence: Peggy Caserta and Seth Morgan had both failed to meet Joplin the Friday immediately prior to her death, October 2, and Joplin had been expecting both of them to keep her company that night.
Split into simpler sentences: Peggy Caserta and Seth Morgan had both failed to meet Joplin the Friday immediately prior to her death, October 2. She had been expecting both of them to keep her company that night.