Book excerpt: As St. Patrick’s Day nears, a retired FBI agent must solve a sinful crime near a small-town convent: “[An] engrossing murder case . . . enjoyable” (Publishers Weekly). Her childhood friends wanted careers, but Brigit Ann Reilly spent her youth looking forward to her wedding—her wedding to God. When she finally gets to don the habit, her new order sends her to Maryville, where a former sister is poised to become Rome’s first Irish-American saint. Brigit has no time to worry about Vatican politics. She’s about to become a martyr herself. Brigit is found dead in the basement of her local library, her corpse swarming with ten poisonous water moccasins. When ex-FBI investigator Gregor Demarkian hears of her death, he is puzzled by two things: Water moccasins are not native to upstate New York, and Brigit died of hemlock poisoning, not the snakes’ venom. As Maryville whips itself into a pious frenzy in search of evidence for its hometown hero’s sainthood, Demarkian will attempt his own miracle by finding justice for the murdered young nun.