The Blood Red Sea

When the salvage of the 400 year old silver coin hoard from a sunken ship is completed, the leader of a Marine Salvage team, Tosh Walker, is found dead with a stab wound to the chest. The evidence leads to prime suspect, rival treasure hunter, Newton Farrell, who argued with Walker earlier; but he is alibied by Catherine at the time that Walker's wife received a phone call from Walker claiming Farrell had stabbed him.