Top: Stayner worked as a maintenance man at the Cedar Lodge, where Yosemite visitors often stay. Bottom: The idyllic cabin in the southwestern corner of the park that was Armstrong's home, and the site of her abduction.

On March 19, a hiker found a burned-out Pontiac on a logging road near the northeastern edge of the park, about 100 miles from the Cedar Lodge. It was Carole Sund's missing rental car, and her charred, bound body was found stuffed in the trunk alongside the body of Pelosso. One week later the FBI, acting on an anonymous tip, discovered Juli Sund's corpse dumped in heavy underbrush by an overlook at the Don Pedro Reservoir, several miles from the logging trail where the car had been found. Her throat had been cut.

The murders were particularly unsettling, of course, because of where and how they had occurred. Not only do such crimes violate our sense of an idyllic setting, but they represent everyone's worst wilderness nightmare come true: the unseen predator who creeps out of the darkness and then disappears back into the shadows of the forest without a trace. It hardly helped that such fears are belied by statistics: Of the four million visitors to Yosemite last year, just 15 were victims of violent crimes, a 70 percent drop from six years earlier. Homicides in the 54 national parks are rare; indeed, 64.5 million visitors thronged the parks in 1998, and remarkably, there were no murders. Before Armstrong's death, the last homicide inside Yosemite's boundaries occurred in 1987, when a man pitched his wife off a precipice to collect on her insurance policy. According to a statistician at the University of Florida, the odds of being murdered in a national park in 1995 were about one in 20 million—less than the odds of drowning in one's own bathtub.

Until the Yosemite murders, perhaps the most terrifying crime against women in the national parks occurred in May 1996, when two experienced backpackers, Julianne Williams, 24, and Lollie Winans, 26, were knifed to death at their campsite a few hundred yards off the Appalachian Trail in Virginia's Shenandoah National Park. The two women had been out for a five-day circuit hike in the park when they were attacked; no suspect has been arrested in the killings.

With the murders in Yosemite Valley, the dual nature of the wilderness—the threat lurking behind the beauty—came again into unnerving focus. By last spring the FBI was centering its investigation on two suspects from Modesto, ex-convicts and methamphetamine users who had had violent run-ins with police in the days after the Sunds and Pelosso vanished. Michael Larwick and his half-brother Eugene Dykes were both being held in the Modesto County jail—Larwick on charges of shooting a Modesto police officer, Dykes for drug possession and parole violations. On background, FBI agents told reporters the two men had been linked to the murders through acrylic fibers analyzed at the FBI laboratory in Washington and through self-incriminating statements made by Dykes. In June the chief of the FBI's Sacramento office, James M. Maddock, confidently announced that "we have all of the main players in jail, but we are in no rush to charge them."

Then Armstrong's mutilated body was discovered. Although the clumsiness of that crime contrasted sharply with the methodical coverup that followed the Sund-Pelosso murders, Armstrong's beheading spread fear through Yosemite that the killings were connected—and that the FBI's investigation had gone awry. Park rangers received a flood of phone calls from parents and youth group leaders asking if certain areas of the park should be avoided; requests for guided hikes—especially from women—rose sharply.

Almost immediately, authorities received a lucky break: A park employee had noticed a blue and white 1979 International Scout parked near Armstrong's house the night of her death, and police had issued a be-on-the-lookout alert for the vehicle. On the afternoon of July 22, two rangers spotted the Scout, parked on the shoulder of California 140 in the Merced River Canyon, about 12 miles from the western entrance of the park. Descending to the rocky riverbank, one of the rangers, accompanied by a Mariposa County detective, came upon a handsome, solidly built man smoking a joint and sunbathing in the nude. He calmly identified himself as Cary Stayner and said he was employed as a handyman at the Cedar Lodge. The officers confiscated his marijuana and let him go. But shortly after that encounter, FBI investigators compared tire tracks at the crime scene with photographs of Stayner's treads—and got a perfect match. Two days later, the handyman was eating lunch at Laguna Del Sol, a "clothing optional" resort near Sacramento, when the cops took him into custody, drove him to Sacramento, and booked him on suspicion of murder. Stayner, 38, confessed to the murder of Joie Ruth Armstrong and then dropped a bombshell: He had also abducted and murdered Carole and Juli Sund and Silvina Pelosso. He told the FBI that he had fantasized about hurting women since he was a child and that he had been unable to stop his compulsion to kill.

For five months, it now appeared, the killer had been living under the noses of investigators—fixing leaks and handing out bed linens at the Cedar Lodge until the urge to murder had struck again. Agents had interviewed Stayner twice in the early stages of the probe but had dismissed him as a suspect. He seemed like too nice a guy, too ordinary, they said. Not only that, but Stayner's background—his own family had been victimized by a similarly monstrous crime—made the idea that he had metamorphosed into a violent predator almost unimaginable.

Photos: Timothy Archibald