A judge on Monday found a woman guilty but mentally ill in the shooting deaths of her three teenage sons, whom she feared had become evil clones or robots.

Cynthia Lord, 45, looked momentarily puzzled as Alaska Superior Court Judge Philip Volland read the verdict in the nonjury trial.

"The evidence is overwhelming that Ms. Lord engaged in a deliberate, conscious and detailed plan to kill her three sons," Volland said, adding, "the evidence is undisputed that Ms. Lord suffers from a severe, disabling mental illness."

Lord sat hunched forward, her pallid face in a perpetual daze and her coarse brown hair hanging loose down her back.

During an 11-hour period in March 2004, prosecutors say, Lord shot Christopher, 19, as he played video games; Michael, 18, as he slept; and Joseph, 16, after he came home from school. They each had a single gunshot wound to the head, according to court documents.

Lord testified this month that she killed the boys because she feared they had become evil clones or robots. She said she would have killed her 15-year-old daughter, too, had the girl been in the apartment.

Lord read a letter to the court in her unwavering monotone: "Evil" was "telling me I have to kill the kids, I have to kill the kids right now, tonight."

She told police she planned for months to shoot her sons, buying a gun in October 2003 after she had settled on her decision.

Lord will remain at the Hiland Mountain Correctional Center, the state's female prison, until her sentencing on Aug. 24. She was convicted of three counts of first-degree murder, could face up to 99 years in a psychiatric institute and could serve part of that sentence in jail if she is ever found mentally stable.

Kacie Carlson, who dated Michael, said she believes Lord simply wanted to keep her boys from moving out of the house. "I agree that she's ill and that she does need help, but at the same time it's hard because I feel like she should really be in jail," she said, her voice breaking.

Sarah Raffuse, 25, who was a cousin of the boys, said through tears that she was the only family member in the courtroom Monday.

"It's the best thing we could've hoped for," Raffuse said of the verdict.