Right on the heels of his first adult novel (Murphy's Herd, a 1989 western, not reviewed) comes this skilled but derivative cops-vs.-serial-killer story from Paulsen, a prolific and two-time Newbery-winning children's author. Paulsen trumpets his new-found adult subject matter with a vengeance: page one finds the unnamed serial killer, as a child, graphically molested by his mom; a few pages and decades later, a janitor at Denver's Stapleton Airport finds a woman's severed breast in a discarded bag. Into this swamp wades Denver homicide cop Ed "Push" Tincker, strong but sensitive--the kind of cop who gets drunk and obsessively drives by his ex-wife's house--and not beyond stepping outside the law to see justice done. "Please don't let this be a cutter," Push hopes, but of course it is, a maniac who--as it's gradually revealed--is not only reenacting Aztec blood rituals, but is an airplane pilot. Could he be the shadowy pilot-husband of the woman with whom Push is having a torrid affair? Sometime after the killer outwits a police ambush and snuffs Push's partner, Push starts to think so, and so do we; but author Paulsen's not that blatant, and the killer turns out to be another pilot altogether. Determined not to let this madman off ("If he arrested Harvitt and proceeded through normal channels the son of a bitch would skate. . .Harvitt had to die"), Push buys a first-class seat and flies Harvitt's next flight to Seattle--a set-up for the exciting return flight and novel's finale, when a crazed Harvitt aims his plane like a javelin for Salt Lake City's Mormon Temple as Push muscles up for some do-or-die heroics. A mess of clichâ€šs (for a more original Aztec-ritual serial-killer scenario, see William Heffernan's Ritual, p. 74)--but all handled with expert care and rotated at such a rapid pace that the final result is satisfyingly gripping, if familiar, entertainment.