Chris Jensen, the Bhasins' good friend and neighbor, is disheartened by the tragedy.

"We were very close to them," he says. "We saw them almost every day. My wife babysat Pamela and Alec after school, and I was like a second father to them. It's a very painful thing to go through for all of us."

Jensen describes Monica as an outgoing, intelligent and kind person.

"She was a very devoted mother. She always did the best for her two children," he says.

According to Terrance Helm, public information officer for the county sheriff's department, county sheriff's deputies found Monica and her two children dead in their apartment unit on Feb. 13.

Some concerned neighbors had asked the sheriff's deputies to conduct a welfare check on the family because they had not seen or heard from Monica and her children for a few days.

Although initially there was speculation that the deaths were a murder-suicide, the autopsies suggest that all three died from carbon monoxide poisoning from the heating system in their home.

According to another neighbor, who asked not to be identified, Monica's residence was an old apartment building, a structure unlike most dwellings in Cupertino.

"They weren't wealthy. And being a single mother, Monica had a hard life," said the neighbor, a good friend of Monica's ex-husband, known as A.J., who moved away about a year ago after the couple divorced.

The neighbor is especially disheartened by the death of young Alec.

"He was the cutest thing on earth," he says. "He loved to talk. He had a voice like a chirping bird. And he was always smiling."

"I saw the children about two weeks ago," he continues. "I was out putting something into my car, and they were holding hands and walking home together. Alec smiled at me when he passed by. That was the last time I saw them."

According to Jensen, Monica, who worked at Sun Microsystems, was engaged to get married in the near future.

"They were so kind, loving and happy. It's just very sad," he says.

About 300 people attended a candlelight vigil organized by friends and neighbors on Feb. 15. Funeral and cremation services took place on Feb. 16 and 20, respectively.