Agatha Christie 
Ingots of Gold [PDF ebook] 

During one of the Tuesday Club meetings, Raymond West tells his story. In a small coastal town, he befriends Newman, a millionaire entrepreneur who sets out to discover gold bars lost among the wreck of an old Spanish galleon. Inspector Badgoworth is investigating the same case. One night, Newman is kidnapped but is eventually found at the bottom of a ditch. The millionaire claims to have seen a group of sailors transporting the gold, but the ingots do not appear. What really happened? Who has the treasure? As always, Miss Marple, will get to the truth.