A 78-year-old woman who had shown a neighbor a threatening note apparently left by an intruder was strangled and her apartment was set afire to cover up the crime, police said today.

Louise Paciarello was dead from strangulation, not the fire, when her body was pulled out of her smoky, first-floor apartment Wednesday evening in Yonkers, a suburb north of Manhattan, the Westchester County medical examiner’s office said.

Paciarello, a retired nurse’s aide, had lived in the Kristensen Homes, a senior housing complex, for 14 years and rarely left the apartment building except to go to the store, according to her sister-in-law Madeline Paciarello.

“She was such a quiet soul,” she said. “She was a very good person. They don’t come any better than her.”

Police have no suspects or leads, Detective Captain William Cave of the Yonkers Police Department said. He said the fire was suspicious because arson investigators discovered two points of origin to the blaze.

Investigators were trying to verify reports from neighbors that she had been threatened.

One neighbor, Walter Astapczyk, said that Paciarello showed him a note, written on a napkin, apparently left by someone who had gotten into her apartment about a month ago.

“It said something like, ‘I was here at 4 a.m. while you were sleeping, and I’ll be back,'” Mr. Astapczyk said.

Paciarello also told him that she heard someone jiggling her door knob during the night about two weeks ago.

A building employee, John Kurilla Jr., said he changed Paciarello’s door lock after she told him about the note.

Most of the woman’s belongings were destroyed in the fire, and police haven’t found her pocketbook, Mr. Cave said. One neighbor told police that the victim kept money in her refrigerator but none was found.

“We don’t know if she removed it herself or if someone else removed it, or maybe she never really kept it there,” Mr. Cave said.

Mr. Cave said Paciarello was very conscientious about keeping her door locked.