A strong debut for historian/editor Mayor, who is map-precise in his description of Brattleboro, Vermont, and painstakingly clear in his account of semen-typing. Someone wants the Kimberly Harris murder case reopened and is forcing the cops to do it by murdering a former juror, harassing another, framing yet another, and so forth. Why? To avenge the pregnant, sexually molested, and murdered Harris? To avenge janitor William Davis, a black man in prison for the crime? Lt. Joe Gunther doesn't know, but ""Ski Mask"" keeps prodding--until complex semen-typing reveals that Harris was pregnant by one man and attacked by another, who probably had Cushing's disease and, as a result of medication, suffered a temporary hunchback. Pharmaceutical sleuthing leads Gunther to Leatheron, Inc., employee Steven Cioffi--who, it seems, was blackmailing the CEO and who was also Harris' married lover. Before Gunther can keep him in protective custody, however, Ski Mask gets to him with crossbow (!) in hand. His reason: parental/filial sexual obsession. Gunther deflects Ski Mask's aim just enough to save a life--and just in time to understand that CEO Telcher was as distraught as Ski Mask about Kimberly's death; it was Cioffi's convoluted way of keeping his blackmail scheme alive. Widower Gunther is admirable; and author Mayor has a strong foundation to work from for book two--a book to look forward to.