Tricky locked-room puzzle from Canadian resident Godfrey, who sets her user-unfriendly mystery in a Toronto data-processing company. Executive headhunter Jane Tregar's assignment: find a new V.P. of Finance for Brian Taylor's company to replace the cigar-smoking Gary Levin, who died of a heart attack--or did he? At 12:55 a.m., the computer he was working on crashed; when he went next door to boot it up, he keeled over and died. And if his death was natural, why, wonder the BTS executives, did the console-printer message say, ""That will teach the son of a bitch""? As rumors fly, BTS stock dips and its in-the-works merger with an American company is threatened. To solidify, CEO Taylor wants Jane to find a replacement now. Unwilling to place a man in a possibly deadly atmosphere, Jane plays detective and learns: only five people had the password to the program that Levin was using; only the same five knew he would be in the office at that time; all five had solid alibis, including top honcho Taylor; Martha Gruen, V.P. of human resources; Tom Henege, V.P. of sales and marketing; comptroller Robert McDonnell; and Martin Kaplan, V.P. for customer support. Before the whodunit and how-it-was-done become clear, Jane decides the planned merger was really a takeover with a ""green mail scenario,"" meaning that Taylor wanted out of his own company and needed the green-mail buyback money to finance his new company venture--a scheme that he needed a malleable Finance V.P. to wrangle, without letting his other V.P.s in on the double-dealing. On confronting the executives, Jane wrings a confession from the culprit; then deftly explains how murder was accomplished (which ought to make nonsmokers of us all). Above-average computer byplay and wheeler-dealer shenanigans, but not much verbal panache. Lacks the Emma Lathan wit and acidity but equals the expertise.