Erle Stanley Gardner 
The Case of the Turning Tide [EPUB ebook] 

District Attorney Frank Duryea had more than a simple murder case on his hands. Had someone killed both Addison Stearne and C. Arthur Right and then vanished? Or had it been a murder and a suicide? And, in either case, who died first? A vast fortune depended on the answer. The obvious suspect was Nita Moline, who claimed she discovered the bodies, rushed up on deck and fainted. However, nobody had seen her come aboard. And through the tangled web of evidence, there seemed to be more than one mystery. Fortunately for Frank Duryea, his wife’s grandfather – the black sheep of a wild family – came for a visit and got in everybody’s way.