The Silver Bullet by Fergus Hume — Read

The surprising discovery that the bullet was of silver, elevated the crime from the common-place to the romantic. That an old-fashioned weapon should have been used in these days when firearms have reached such a pitch of perfection, was remarkable enough, but that the assassin should have reverted to the superstitions of the Middle Ages for his missile, was almost beyond belief. In spite of her quick brain, Bess could not come to any decision. Failing a discussion with Dr. Jim she resolved to leave the vexed question at rest.

All the same she did not pause in her detective work. Having followed up one clue, until it ended -- for the time being -- in nothing, she hunted about for another. So far she had made two discoveries. The pistol which Joyce declared he had received from Don Manuel was certainly the weapon with which the murder had been committed; and the bullet was of silver. But this knowledge resulted in nothing. Certainly it cast a strong suspicion on the Mexican; but that part of the puzzle Bess felt she could safely leave to Herrick. So far as her particular business was concerned she could do no more, until she heard her colleague's report. Pending this, she began to work in a different direction. It occurred to her that she had never questioned Sidney about his doings in the Pine wood on the night of the murder. Possibly he might be able to supply some clue to the mystery.