The House of Mammon by Fred M. White

John Sairson's wonderful constitution was standing him in good stead. A specialist from London, along with a number of assistants, had, after a deal of trouble and anxiety, extracted a bullet from the wounded man's head. This had passed into the hands of the police, who were satisfied that it afforded a good clue.

But whatever the constables might think, Inspector Skidmore admitted to Lugard that it would not help them. In the whole course of his experience, he said, he had never seen a missile like it before. It was nothing but the thinnest shell of lead, capped with tin. The thing had curled up like a threadpaper; indeed, how it had penetrated Sairson's skull at all was in itself a mystery.