A woman who previously served prison time for second-degree murder was arrested Wednesday and accused of setting a blaze that killed six people and gutted much of a historic brick building in Reno's downtown casino district.

Valerie Moore, 47, a casino cook, was arrested on arson and murder charges stemming from Tuesday night's blaze at the Mizpah Hotel that police said began when she set fire to a mattress. It was the city's deadliest blaze in more than 40 years.

About 30 people were injured, some of them after they leaped out the windows of the three-story building, which was primarily a residential hotel.

Crack the case in FOXNews.com's Crime Center.

Hotel workers and neighbors, who described Moore as "nice" and a "good tenant," said she had been drinking and may have lost control after an argument with another tenant.

Moore was booked into the Washoe County Jail on suspicion of first-degree arson and six counts of first-degree murder. She also faced a parole violation charge, sheriff's Deputy Brooke L. Keast said.

Police said 60 to 80 people were inside the 84-year-old, recently renovated hotel when the fire started. It quickly engulfed the north wing of the hotel, near Harrah's casino. None of the downtown high-rise hotel-casinos were threatened.

Firefighters said they did not know of anyone still missing in the fire, but they had yet to search some areas. The roof collapsed, and authorities said the building would have to be shored up.

One hospital reported that two people were hospitalized in critical condition, and a third was flown to a burn center in California.

Keast told The Associated Press she had no immediate details of the original charge against Moore but confirmed that she served time in prison for second-degree murder.

State corrections records obtained by the AP show Moore was convicted on Sept. 24, 1987, in Washoe County District Court for a killing in February of that year. She started serving two life sentences on Nov. 5, 1987, but was released on parole in June 2005, state corrections records show.

Authorities said Wednesday there was no record that Moore had hired a lawyer.

Neighbors and hotel workers described Moore as a normally pleasant woman.

"She didn't seem like a crazy person," said Maxie Birch, 42, who lived down the hall from Moore. "But something happened last night to push her over the edge. She just flipped. I don't know what caused her to flip."

Steven Purcell, 53, the hotel's front desk clerk, said Moore asked him to escort her from a nearby liquor store to the hotel late Tuesday afternoon.

"She was a really good tenant. She just had way, way too much to drink yesterday, causing trouble all day," said Sharon Steele, the hotel's general manager.

It was Reno's deadliest fire since 1962, when six people died at the Golden Hotel, said fire department spokesman Steve Frady. He said the Mizpah had smoke alarms but not sprinklers, which was allowed by city code because of the building's age.

The Mizpah was built in 1922 and added to the National Register of Historic Places in 1984. Fire officials said they did not know whether the building could be saved.

"It was just gorgeous, and now it's all gone," said Steele. "It's a brick building. I don't know why it burned so fast."

Visit FOXNews.com's Crime Center for complete coverage.