Relatives gathered at Roger Jessup park in Pacoima, selling homemade food to try to raise money for memorial services.
The children ranged in age from 6 months to 3 years. Their mother, Lilliana Carillo, confessed to the killings in an interview with Bakersfield's KGET-TV.
"I drowned them. I did it as softly ... I don't know how to explain it," Lilliana Carrillo said Thursday in a disturbing jailhouse interview with KGET-TV. "I hugged them. I kissed them. I was apologizing the whole time. I loved my kids."
Carrillo told the Bakersfield television station that she killed the children to protect them from their father, who she claimed was involved in human trafficking.
She said she wished her children were still alive, adding, however: "I prefer them not being tortured and abused on a regular basis for the rest of their lives.''
Carrillo identified the children as Joanna Maria, 3; Terry Joseph, 2; and Sierra Sequoia, 6 months.
"I love you and I'm sorry,'' was the last thing she said to her son and daughters, according to Carrillo.
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The victims' grandmother found their bodies about 9:30 a.m. Saturday in an apartment in the 8000 block of Reseda Boulevard, according to the Los Angeles Police Department. Carrillo was nowhere to be found.
Identified as the suspected killer, she was arrested hours later in Tulare County, nearly 200 miles north of the scene.
The Associated Press contributed to this report.