AUTHOR PHILIP CAPUTO WAS VACATIONING in remote southern Arizona when he heard a partial, static-filled news report on the car radio. All he made out at first was that 16 children had been killed in their school gym by a man who then took his own life (see page 42). "My God," thought the Pulitzer Prize-winning journalist and father of two now-grown children, "this is what I wrote about, but it's even worse."

Indeed, Caputo's new book, Equation for Evil, eerily anticipates the Dunblane slaughter. The novel tells of a loner named Duane Boggs who ambushes a school bus and murders 14 children and the driver before killing himself with a gunshot to the head. Caputo, 54, based his fiction on the 1989 case in Stockton, Calif., in which 26-year-old drifter Patrick Purdy opened fire with an AK-47 assault rifle on an elementary school playground, slaying 5 children and wounding 29 others before ending his life.

Caputo's first fear was that "some nut had picked up my book, read it and decided to do something even worse than what my fictional Boggs did." He was relieved on that account when he later learned his book is not yet available in Great Britain. Still, Caputo, who spent 10 weeks in Stockton researching Purdy's crime, was struck by the similarities between it and Scottish killer Thomas Hamilton's bloody rampage in Dunblane. Most obvious and horrifying, he says: the targeting of children. "These men choose children essentially because they're cowards and they're terrified by the possibility of resistance," says Caputo. "More important, Purdy and possibly Hamilton, both of whom felt rejected by the world, wanted to inflict upon society a pain as great as they felt society had inflicted on them. What greater way to cause society pain than to kill its most innocent members?"

Caputo, having interviewed members of the victims' families and residents of Stockton, adds that it is virtually impossible for a community to recover fully from such a tragedy. "I visited Stockton two or three years after Purdy, and the massacre was still very real to the people there," he says. "It can't heal in the sense that you can't integrate a horror like that into your life. It remains a scar forever, at least for the generation that witnessed it."