San Jose, Calif. ? A jury decided Wednesday that Cary Stayner should die for killing three Yosemite National Park tourists in 1999, rejecting defense pleas to spare a mentally ill man twisted by genetics and a traumatic childhood.

Jurors took just six hours to return their recommendation to the judge, who has the option of sentencing the 41-year-old Stayner to life in prison. Sentencing was scheduled for Dec. 12, and an appeal is automatic.

The courtroom was silent after the decision was read. Stayner showed no visible reaction.

The killings terrorized communities along the rugged Sierra Nevada and went unsolved for more than five months. In that time, Stayner beheaded a park naturalist, a crime for which he is serving a life term in federal prison.

Carole Sund, 42, her daughter, Juli, 15, and their Argentine friend, Silvina Pelosso, 16, vanished on a trip to Yosemite. The elder Sund, who once honeymooned at the park, took the girls there as a treat before Pelosso returned home.

Stayner noticed the three one night through an open curtain in a room at the Cedar Lodge, where he worked as a handyman. The mother was reading a book, the girls were watching a videotape and, according to his confession, Stayner saw “easy prey” to fulfill a longtime sexual fantasy.

Carole Carrington, Carole Sund’s mother, said the verdict did not end the family’s grief, but marked an end to “part of the problem.”

“Condemning Cary Stayner to death is not happy for anybody, but it’s justice,” she said.

Stayner’s defense conceded prosecutors had the right man, but said he didn’t deserve to die because he was in the throes of a major mental illness caused by a misshapen head, his childhood and bad genes. They said he heard voices in his head.

Stayner’s lawyer, Marcia Morrissey, said a key issue in her client’s appeal would be that his parents weren’t allowed to detail his troubled upbringing.

“This fight won’t be over for Cary Stayner until he gets a fair trial,” Morrissey said. “And he hasn’t gotten a fair trial.”

Stayner never testified, but the prosecution used his lengthy tape-recorded confession to show he was cunning, methodical and went to great lengths to cover his tracks. In court, Stayner blocked his ears as the tape was played.

Stayner said he tricked his way into the tourists’ room by pretending to check for a leak and then pulled a gun and said he was a desperate man needing money and a car. He bound them with duct tape, and, with the girls in the bathroom, strangled Carole Sund and stuffed her body in the trunk of her rental car.

He strangled Pelosso in the bathroom after she wouldn’t comply with his sexual demands, then spent the rest of the night molesting Juli and trying unsuccessfully because he was impotent to rape her.

The next day, he drove the girl to a scenic overlook and carried her “like a groom carrying a bride over the threshold” to a grassy hillside, where he sexually assaulted her one more time, told her he loved her and slit her throat. He torched the car.

Stayner dropped Carole Sund’s wallet on a Modesto street to mislead authorities, and sent a taunting note to the FBI to throw them off his trail.

The killings puzzled law enforcement for months.