Manna from Hades
(Book)

The day after collecting donations, elderly widow Eleanor Trewynn and the vicar's wife find the dead body of a longhaired, scruffy-looking youth hidden in the stockroom of the charity shop. Then they discover that some donated jewelry thought to be fake is actually very real, very expensive, and the haul from a violent robbery in London. Making matters more complex, the corpse found in the storeroom is apparently not one of the robbers.