A mother already charged with drowning her 1-year-old daughter will face an additional murder charge over the death of a 5-year-old sibling, authorities said Thursday.
Prosecutors expect to file an amended criminal complaint containing the second murder charge before the scheduled arraignment of Lorna Valle on Friday, Los Angeles County district attorney's spokeswoman Jane Robison said.
Valle's daughter, 5-year-old Marian Taque Valle, was declared brain dead on Sunday. She was removed from life support and her organs were harvested on Wednesday. An autopsy was planned.
Valle, 32, currently is charged with the girl's attempted murder and with killing Marian's 1-year-old sister, Lindsay. She remained jailed Thursday.
The girls' father, Jose Humberto Lopez, told police that he returned from a store on Feb. 15 and discovered his wife trying to drown the children in a tub. Firefighters answering a 911 call found the girls unconscious and not breathing in a converted garage behind a main house.
The younger girl died a few hours later.
Acquaintances said the mother had been struggling with depression.
If convicted, Valle could face 50 years to life in prison.
Another mother has been charged with killing her infant son last fall by tossing him from a hospital parking structure in Orange County.
Sonia Hermosillo, 32, of La Habra is charged with murder and child abuse in the August death of 7-month-old Noe Medina Jr. She remains jailed and a court must decide whether she is mentally competent to stand trial.
Prosecutors said Hermosillo tossed the child from the fourth level of the parking garage at Children's Hospital of Orange County then validated her parking ticket before driving away.
Her husband, Noe Medina, said his wife suffered from severe post-partum depression and was distraught because their son had several medical conditions, including one that required him to wear a helmet to reshape his head.
Prosecutors said Hermosillo removed the helmet before tossing the child over the railing.