LOS ANGELES (AP) _ The Peppertree condominiums where Meta Frances Murphy lived peacefully and died violently are built around a sunny courtyard that encouraged neighborly camaraderie.

Whenever Gitta Ruivenkamp needed emotional support, she would call on Ms. Murphy, a 62-year-old librarian, and look through her collection of Christian Science literature.

Therese Lebao, 17, recalled the time she was locked out of her condo. The mother and stepfather of three teen-age sisters charged with killing Ms. Murphy helped her get in, she said.

The trust between neighbors - shaky because of Ms. Murphy's slaying in November - again was shattered June 12 when police arrested the girls, ages 13, 16 and 17.

They have pleaded innocent in juvenile court.

''It did something to this community,'' Ms. Ruivenkamp said. ''People have moved out. I'm alert all the time when it's dark. I don't have the feeling of coming home and feeling good about being home.''

Ms. Murphy's body was found neatly covered with coats in an upstairs bedroom closet. She had been bludgeoned in the head and stabbed numerous times. Police said she had wounds on her arms from fighting off her attackers.

There was no sign of forced entry or robbery. Detectives said bloody fingerprints in the apartment linked the girls to the crime.

Alex Ross, the 16-year-old's lawyer, would not comment on the case except to say, ''We do have a defense.''

What is especially baffling about the slaying, prosecutors said, is the apparent lack of a motive.

The sisters were, at one time, quite friendly with Ms. Murphy. She would take care of their cats and was one of several neighbors who regularly gave the girls snacks and sodas.

''That is what makes this case so puzzling and so fascinating,'' said Tom Rubinson, deputy district attorney.

One neighbor, who spoke on condition of anonymity, said that a few months before her death Ms. Murphy told the girls they could not eat at her home anymore. The neighbor said Ms. Murphy later told her the situation with the girls was getting worse.

On the surface, all seemed well in the family of the three girls. Neighbors described the mother and stepfather as pleasant and clean-cut, though no one seemed to know them well.

The family has refused to comment. A man who answered the door of their condominium said the girls' mother had nothing to say.

Next door, Ms. Murphy's condominium is locked and the curtains are drawn. Neighbors are feeding her three cats until homes can be found.

A tearful Kay Kirkpatrick described Ms. Murphy as an intellectual woman who loved reading, classical music and crossword puzzles. She was single and had no children, Ms. Kirkpatrick said.

''She was so sweet,'' Ms. Kirkpatrick said. ''She was the last woman in the world you would think something like this would happen to.'