BLEEDING HEARTS

Four years after pop psychologist Paul Hazzard was acquitted of stabbing his second wife, his then-mistress Candida DeWitt, whom Paul had tried to sell to the police as a better suspect, is planning a tell-all memoir. In the meantime, Paul, his love-your-addiction empire in ruins, has gone on to greener ($$$) pastures: stolid Hannah Krekorian of Philadelphia's Armenian neighborhood, a longtime friend of retired FBI serial-killer expert Gregor Demarkian's (A Stillness in Bethlehem, 1992, etc.). Imagine the neighbors' surprise when Candida shows up brandishing an invitation at Hannah's Valentine's Day party- -and their further surprise when, after an ugly scene between his once and future women, Paul is found stabbed to death. Despite some wide-eyed infatuation with the ghost of Agatha Christie: a rattling good puzzle, a varied and appealing cast, and a detective whose work carries a rare stamp of authority. Whether or not you're already a fan of Haddam's holiday-themed mysteries, this one is a treat.