Complex sentence: Lem agrees and gives Delia a note to Dan to say so--when Delia returns to the office to confront Dan once again, she finds him dead and is arrested for his murder, due to her earlier incautious statements.
Split into simpler sentences: Lem agrees and gives Delia a note to Dan to say so. When Delia returns to the office to confront Dan once again, she finds him dead and is arrested for his murder, due to her earlier incautious statements.