Los Angeles police believe she is the sole suspect in the murder of her three young children, identified by their godmother as three-year-old Joanna, two-year-old Terry, and six-month-old Sierra.
The siblings were found dead inside an apartment in Reseda on Saturday morning.
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"They were the happiest kids I ever had around in my life and I never thought that we would have to lose them so soon," Gabriela Gomez said.
In court documents filed in Tulare County last month, the father of the children says that Carrillo "started showing signs of postpartum depression" after the birth of Terry.
"Her condition has worsened," he writes. "She is not taking care of herself and has lost touch with reality. She is extremely paranoid and acts impulsively and erratically."
He adds that she believes she is responsible for COVID-19 and that there is a pedophile ring in the city of Porterville.
In late February, he says Carrillo took their children away and wouldn't tell him where they were.
He wrote, "I am afraid for my children's wellbeing while they are in (her) care," before asking the court to give him temporary custody and that Carrillo receive a psychiatric evaluation.
Temporary custody was ordered to the father, but on March 26, the judge awarded joint custody and set another court date for April 14.
Temporary custody orders and jurisdictional issues were to be discussed at that time, but the children were killed just days before the hearing could be held.
The LA County District Attorney's Office hasn't filed charges against Carrillo yet, but prosecutors say the case is on their radar.
Meanwhile, a GoFundMe account has been set up to help the children's father.