Somebody calling himself Thanatos, the lord of death, is writing letters to Las Piernas News Express reporter Irene Kelly (Sweet Dreams, Irene, p. 19, etc.), whom he calls Cassandra, obliquely prophesying a series of murders--and then making good on every prophecy. The first victim, dubbed Clio, is a promiscuous history professor at Las Piernas College (Calif.) who likes her men young; the second, Thalia, is the owner of Rosie's Bar and Grill. By the time the third is reported--it's Ceyx, a manufacturer of aircraft fasteners--Irene and her fiancÇ, Det. Frank Harriman, know a lot about the victims: They're all 54 years old, the children of mothers who did wartime work in the local Mercury Aircraft plant. But is that information enough to get a lead on Thanatos, who's taken to harassing Irene in a more insinuating way by leaving the lights on in her car and breaking gently into her house? As Irene and Frank close the net around Thanatos, Irene feels a net closing around her as well. Even if you've read the story of the menaced reporter before, the austere focus and proportion of this effort stand out. No newsy subplots, no socially redeeming value, not even any particular originality. All Burke has done is take one of the hoariest clichÇs in the business--the letter-writing serial killer--and make it as fresh and chilling as a winter sunrise.