Mom knows best when a daughter takes up with a guy who's wrong, wrong, wrong. Not that Kevin Glade doesn't try to make a good impression. A Cornell scholarship student who sends Laurie Lewishon poems and jewelry, he's polite and presentable to a fault; even his room is neat. Now if only he were Jewish--and if only he weren't really an impostor named Billy Owens, on the run from Kokomo, Indiana, where he killed the high-school sweetheart who thought he was getting a little too possessive. Billy did such a good job covering up his murder of April Meadows that even her parents, though they suspect she didn't just run away from home, are a million miles from suspecting him. But Laurie's shrewd mother and grandmother know from the get-go that there's something funny about relentlessly ingratiating Kevin. Jessica is determined to unmask him; but for every step she takes--uncovering holes in the biography he's sold Laurie, revealing the unhealthy intensity of his attachment to her, linking him to a conveniently dead drug user, even exposing his poems as plagiarisms--there's some plausible explanation. Meanwhile, back in Indiana, the savvy Inspector Sandy Ungar gets a hunch that the departed Billy killed April Meadows--but she runs into the same discouraging pattern of soothing explanations at every turn. How long will it be before these two worrywarts finally run into each other--and what will Kevin be doing with Laurie by the time they do? That's the one and only question Jacobs (There Was a Little Boy, 1990) has on her mind, and if you don't know what the answer will turn out to be, then this is the book for you. A bustling exercise in forestalling the obvious that's just the ticket for Mary Higgins Clark's less demanding fans.