"Who can it be?" said May, gazing at it. "I've seen that face before."
"So have I," answered Dowker with decision, "there is something in it familiar; but is this the locket you have seen Lady Balscombe wear?"
"Yes--and this is the chain."
"So far, so good," said Norwood, taking up the arrow-head, "but what is this?"
Dowker looked at it for a moment, and then smiled.
"I would advise you to take care of that," he said quietly, "it's poisoned."
"Poisoned!" echoed Norwood, and quickly replaced it in the drawer, "how do you know?"
"Because I am certain that it is the weapon with which the crime was committed--we were misled by the Malay kriss, but this is a certainty."
"Then you think Sir Rupert guilty?" asked May in dismay.
"Sir Rupert is jealous of his wife--he follows her on that night, knowing she is going to elope--meets her in Piccadilly, and is seen following her by one witness--is overheard having angry words with her by a second, who also sees him wrench a locket off her neck--his wife is found dead--and in a secret drawer, known only to Sir Rupert, yourself, and the dead woman, is found the locket and the weapon with which the crime was committed. I think the case is clear enough."