"Why not Alan Mason--counting _both_ ways his initials make the number thirteen?" Trenholm stuffed his hands into his pockets and gazed at her tall, shapely figure, her clear, olive skin, and her great beautiful eyes, and was conscious of an accelerated pulse. He came a step closer. "I have learned that Alan was on the troopship from Vladivostok with his cousin Paul." She started and stared at him aghast. "I can't believe Mr. Mason had a hand in the murder," she declared vehemently. "Call it instinct--or what you will--I believe absolutely that Mr. Abbott's murder was planned and carried out by Boris Zybinn, and I cannot forget that Alexander Nash was Zybinn's neighbor in Toronto. Tell me," she came closer to his side, "has Doctor Nash a parish in Washington?" "No--nor in Toronto." Trenholm stroked his chin reflectively. "I understand that he was a man of considerable means before he married Representative Carter's daughter--and that in spite of the difference in their ages, it was a love match, pure and simple. I think Paul told me that Doctor Nash had retired from the ministry." "O-o-h!" Miriam's exclamation was long-drawn out and Trenholm stared. She gave him no opportunity to question her further. "To go back to the coded message," she began, "have you thought the words 'suicides grave' have any connection with the Mason plot out yonder and the poor suicide--that makes the thirteenth grave--as you pointed out the other day, in that neglected family cemetery?" Trenholm looked at her keenly. "Time will show," he replied, and wondered at her disappointment. "Why do you ask?" "I walked by the graveyard just now," she said hurriedly, "and was amazed to see--" "Excuse me, Miss--Ma'am"--Martha's complaining voice caused Miriam to jump--startled by the woman's proximity. "Dinner will be ready in a minute. I've just telled the folks upstairs, and thought mebbe you'd like to know. There's a couple o' boys outside inquirin' for ye, Sheriff," and, her message delivered, Martha took herself off. Trenholm caught up with her before she reached the kitchen, and drew her to one side. "Martha!" His low stern voice sent a shiver down the woman's back, and the pressure of his hand on her arm tightened. "When did this letter reach Mr. Paul?" and he held before her the thirteenth letter. "No lies, now. I want the truth." "Yes, sir," Martha's quavering tones did not belie her feelings. "Please, sir, that there letter with them queer stamps come the morning Mr. Paul was killed, sir." "No go, Martha," Trenholm shook her slightly. "The postmark shows this letter should have reached Upper Marlboro last week." "I ain't sayin' it didn't," she whined. "But by mistake it was put in Anna's father's box by the carrier; an' havin' sickness in the family, Anna only brought it up on Monday mornin'. I took it from her, sir, and went right up to the room where Mr. Paul was talkin' to Mr. Alan--an' laid it on the table."