Lucas Davenport has seen many terrible murder scenes. This is one of the worst. In the small Minnesota town of Deephaven, an entire family has been killed - husband, wife, two daughters, dogs. There's something about the scene that pokes at Lucas's cop instincts - it looks an awful lot like the kind of scorched-earth retribution he's seen in drug killings sometimes. But this is a seriously upscale town, and the husband was an executive vice president at a big bank. It just doesn't seem to fit. U