A convicted murderer accused of killing 12 people and injuring dozens in a hotel fire pleaded not guilty Friday to arson and multiple counts of first-degree murder.

Valerie Moore entered the pleas three weeks before prosecutors are scheduled to tell the court whether they will seek the death penalty.

Authorities are reviewing the mental competency of Moore, a casino cook accused of setting fire to a mattress Halloween night after arguing with another resident at the 84-year-old, $150-a-week Mizpah Hotel near downtown Reno.

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All 12 victims died of asphyxiation from smoke and soot, investigators said, and another 31 people were injured.

Moore, 47, was paroled in 2005 after serving 17 years in prison for second-degree murder. Prosecutors said she killed a woman who had spurned Moore's sexual advances and argued with her over money.

Outside the courtroom Friday, defense attorney Jennifer Lunt said Moore has a history of mental illness, and that the defense was considering seeking a mental evaluation.

Moore, arrested a day after the fire, is being held without bail on 12 counts of first-degree murder and one count of first-degree arson. Her trial is set to begin Jan. 21, 2008.