LOS ANGELES, NOV. 16 -- Los Angeles police tonight arrested Dorothea Montalvo Puente, the Sacramento woman suspected in the slayings of seven elderly boarders, after being tipped that she had been staying in a downtown hotel since Sunday, authorities said.

KCBS-TV said a man who spoke to Puente in a bar and recognized her from news photographs called the station and reported she was at the Viking Hotel at Third and Alvarado. Police confirmed the identification and arrested her at the hotel.

Earlier, Sacramento Police Chief John Kearns admitted that his officers "made an error" in letting her slip away after discovering the first of seven bodies unearthed in her yard and learning that she had been convicted previously for drugging and robbing elderly acquaintances.

Federal and state investigators had been following leads in California, Nevada and Mexico in search of Puente, 59, who had taken in homeless elderly whom no one else wanted and shrugged off inquiries about their disappearances.

Meanwhile, citing lack of evidence, authorities released John McCauley, 59, a boarder in her baby-blue Victorian house. He had been arrested Sunday on suspicion of helping with the murders.

Kearns said Puente had been treated for cancer in California and Mexico. Before she disappeared Saturday morning, he said, Puente "was being extremely cooperative. We became too familiar with the suspect and too trusting."

"She should have been tailed very closely," he said. "There isn't any excuse as far as I'm concerned why the suspect was not kept under surveillance."

Court papers filed to justify a murder charge and search warrant revealed that Puente was captured while trying to flee to Mexico in 1982 after stealing money from two elderly women and an elderly man. In two cases, the papers said, she had drugged her victims, whom she befriended with an effusive charm noted by many people with whom she came in contact.

A 1982 county probation report said "she had concentrated her criminal efforts on a segment of the community that is the most vulnerable, the ill and the elderly." A psychiatrist's report labeled her a "chronic undifferentiated" schizophrenic.

But, in an emotional letter seeking court leniency, she said she was trying to support 16 poor brothers and sister, and she was released after serving less than two years of a five-year sentence. Other accounts indicated that she had just six siblings.

Court papers show that a police detective left her last Saturday morning at a nearby hotel, where she said she wanted to meet a nephew, and later discovered that she had disappeared.

Police had been alerted by social worker Judith Moise that Alvaro Montoya, a man living at the house, had disappeared and that Puente's story that he had moved to Mexico or Utah did not ring true. A report filed by homicide detective John Cabrera said Puente first denied that Montoya was dead and, after the first body was found, said, "Sir, I have never killed anybody."

The police reports noted, however, that one boarder, who supported Puente's assertion that she had seen Montoya recently, slipped a note to an officer saying, "She's making me lie for her."

Officers also knew before letting her go that Puente, an avid gardener, had been digging trenches and could see residue of lime, often used to speed decay of animal remains, in the ground, the papers said.

On Tuesday, coroners began autopsies on remains of seven persons found in shallow graves in Puente's yard. No cause of death has been reported.

Police and city officials ended their search after digging into every corner of the yard.

Authorities said they had a list of 18 missing persons thought to have lived at the house at one time.