Miriam drew in a long breath. "You may be right, Doctor," she admitted. "I'll get into my uniform after dinner." It was a somber, silent group that drove in the Rolls-Royce from the country cemetery to Guy Trenholm's bungalow five miles distant from Upper Marlboro. Pierre followed the sheriff's directions as to crossroads with indifferent success and Betty finally complained of the rough going and frequent turns. Trenholm lifted the speaking tube as they approached a white gate which opened on a roadway to a picturesque building partly concealed from the road by a number of trees. "Stop here, Pierre," he directed, then turned to the silent man by his side. "I am greatly obliged to you, Doctor Nash, for giving me this lift. Good evening," and he sprang out of the car before the chauffeur had brought it to a full stop. Not pausing to exchange a word with Alan or Betty, aside from a wave of his hat, he strode across the turf. As he reached his front door he thrust his hand inside his overcoat pocket for his bunch of keys and pulled them out, and with them a folded piece of paper. Trenholm stared at the paper as he thrust the key in his front door, and before turning it in the lock, paused to unfold the note. The few lines it bore were unsigned and in an unknown handwriting: Let him who hopes to solve the mystery of Paul Abbott's death find the lost Paltoff jewel. Trenholm's expression was as blank as the other side of the paper. It was unaddressed. He reread the note a number of times, then entered his bungalow. The telephone was in the room he used as library and sitting room. Hardly noticing the police dogs that fawned upon him at his entrance, he sat down before the telephone and quickly got his number. "Hello, constable," he called. "This is Trenholm speaking. Station a guard over the vault where Abbott lies. What's that?--Oh, just a precaution, that's all. Good night!" and he hung up the receiver. Taking out his pipe and tobacco pouch, he stretched his long legs under the table and sat back, the note in his hand. "Which one of them," he mused, unaware that he spoke aloud, "slipped this note in my overcoat pocket?" CHAPTER XII THE HUMAN EYE PABLO, Trenholm's Filipino servant, brought the after-dinner coffee into the library and withdrew with the swiftness and silence which characterized his movements. "Excellent coffee," commented Roberts. He relaxed lazily against the cushioned sides of the big leather chair in which he was sitting and stretched his tired muscles. "It's strong and black. Better have some, Alan." But Alan Mason declined. "I am too jumpy now," he admitted. "Where the deuce is Trenholm?"