A down-at-heel English teacher in Italy goes on a crime spree: in his sixth novel (but first thriller), the British expatriate Parks (the nonfiction Italian Neighbors, p. 658, etc.) turns up the heat, with wonderfully scary results. Morris Duckworth feels trapped. Two years teaching dumb rich kids in Verona and he's still dirt-poor, though what he admires most about Italians is their ``stylishly flaunted wealth.'' The young Englishman mouths off into his dictaphone, scapegoating Dad in London, who physically abused his beloved mother (now dead) and who practically drove the ``pansy/weakling'' Morris from the house. Then, spontaneously, he steals an expensive document case on a train; the ease of the theft gives him a rush, so when one of his richest students, 17-year-old Massimina Trevisan, whom he's been half-seriously courting, runs away from home with her life savings, the temptation to exploit the situation is irresistible. Thus begins a combination elopement/kidnaping that takes the couple on a helter-skelter journey across Italy (though Morris checks in at Verona to assure family and police he knows nothing). Dexterously, Parks shows the occasional thief and habitual liar, the virgin (Morris's best-kept secret) with the raging Oedipus complex, moving down the slippery slope, turning into a full-blown psychopath who's ``far too smart to be a killer'' until killing becomes essential and who lubricates his rationalizations with a profound self-pity. The fact that we never know when the brilliant improviser will fumble his moves like ``a stupid amateur...a boy in a mess'' keeps us on a knife-edge. Parks shows he can juggle with the best of them. His move into the suspense field is a triumph.