A woman who set a devastating hotel fire was sentenced to 12 consecutive life prison terms Friday, one for each person killed in the blaze.

Valerie Moore pleaded guilty in January to the Halloween night murders but said at her sentencing hearing that she did so only to avoid the death penalty.

"I'm sorry for each and every one of your loss, but I did not do this," she said, as some in the courtroom gasped.

Click here to visit FOXNews.com's Crime center.

Washoe District Judge Brent Adams, however, said Moore acknowledged when she entered her plea that she is guilty. Prosecutors would be free to seek the death penalty if Moore seeks an appeal.

Twelve people died of asphyxiation and 31 were injured in the fire at the Mizpah Hotel, an 84-year-old building without sprinklers where rooms rented for $150 a week.

Prosecutors said Moore, who was paroled in 2005 after serving time for another murder, had been angry with another tenant when she set fire to a mattress outside his door.

Victims' families pleaded with Adams to guarantee Moore would never leave prison. Adams also sentenced Moore to up to 15 years for first-degree arson.

Michelle Fletcher shook with grief as she told of losing her only son, 22-year-old Christopher Covert.

"My son never had a chance to shine," she cried. "He was trying to find himself, his own niche in life."

John Elswick said he lost more than his stepson, Jeremy Wren.

"I've lost my beautiful, vivacious wife," he said. "She wishes she were dead to be with her son."

Moore's attorney, Jennifer Lund, said Moore was intoxicated and had been using cocaine the night of the fire, and had no idea the fire would be as devastating as it was. Moore has a history of mental illness but was deemed competent for trial.

Moore, 47, a casino cook, had been paroled in 2005 after serving 17 years in prison for killing a woman who prosecutors said had spurned Moore's sexual advances and argued with her over money.