The mother accused of drowning her three young boys in the San Francisco Bay told relatives the day of the killings that she would "feed them to the sharks," but family members did not take the threat seriously, a sister said Thursday.

Less than a day after Lashuan Harris, 23, allegedly stripped her children naked, hoisted them over a pier safety rail and tossed them into the bay's chilly waters, relatives described Harris as a devoted and loving mother whose life began spiraling out of control when she was diagnosed with a mental illness two years ago.

Now, with Harris in custody and facing murder charges, authorities mounted an intensive effort to recover the children's bodies.

While a Coast Guard helicopter spotted the body of Taronta Greeley, 2, on a beach more than a mile away from where his mother was arrested Wednesday, Treyshun Harris, 6, and Joshoa Greeley, 16 months, remained missing in the bay.

Harris, a schizophrenic who had been living in a homeless shelter, came from a large, close-knit family. Relatives described her as a good mother who was overprotective of her children. They said that she had been ill for two years and that her condition had deteriorated in the past four or five months.

"She doesn't like taking her medication," said the sister, Britney Fitzpatrick, 16. "Once, she told my mom she had thrown it away."

Fitzpatrick said Harris would often talk to herself and claimed to hear voices. Then on Wednesday, she said, Harris made a comment no one believed. "She told my momma once she was going to feed them to the sharks," Fitzpatrick said.