“Just a moment,” broke in Trenholm. “Why did Zybinn use the words ‘thirteenth letter’ to designate the initial ‘M’ on the back of the watch?”
“Because in devising our code we failed to make provision for indicating an initial, expecting never to use one.” Roberts chafed one cold hand over the other. “Had I decoded Zybinn’s last message, I’d have gotten his meaning, however, for that little sketch is the only painting by Paul’s mother on the premises and always cherished by her son. He invariably spoke of the sketch as ‘The Suicide’s Grave.’”
“I told Zybinn that,” admitted Betty. “Great heavens! how I played into his hands—”
“Just so!” agreed Roberts with sneering emphasis. He straightened up, swayed slightly and recovered his balance with an effort. “Come,” addressing Trenholm, “I can stand no more.”
The constable was by his side and Riley at his heels instantly. “We’ll take him to Upper Marlboro, sir,” the former stated, and at a nod from Trenholm, Roberts, with eyes averted from his former friends, left the room, the black shroudlike cloth still thrown about his shoulders—typical in its vague outlines of the shadowed and complex nature of the man.
Mrs. Nash’s overcharged feelings found relief in tears. “There,” she exclaimed, as her distracted husband held a glass of water and Miriam the smelling salts. “I’ll be myself in a minute. Betty, come and tell me why you remained here, instead of returning to Washington with your uncle, and why you lied about your visit to Paul.”
Betty cleared her throat. “You were partly responsible—”
“I?” her aunt regarded her in astonishment.
“Yes. After leaving the house I remembered my promise to Uncle Alexander to telephone you why we were detained, and while he was cranking the car, I jumped out and rang the bell. No one came and I waited and rang again. Looking around I saw that Uncle had driven off. I tried to overtake him and failed, so spent the night here in Paul’s garage, the door being unlocked. Martha found me there in the morning and gave me some breakfast. She told me Paul had been murdered. It was a frightful shock!” Betty drew in her breath. “And I lost my head and ran away; and, to make bad matters worse, denied my visit here.” She turned impulsively to Alan.
“You will never know the suffering I have endured since Monday,” she said, and her voice quivered with emotion. She read his expression, and a look of hope, of joy, flashed up in her face. “Am I forgiven?”