The mother of three young children who were found dead in their Los Angeles-area apartment was arrested Saturday after an hours-long manhunt, during which she is accused of carjacking a pickup truck.

Liliana Carrillo, 30, was captured in Tulare County, about 175 miles north of the crime scene, Los Angeles police said. They described her as “the sole suspect in this case.”

The grandmother of the children, ages 6 months, 2 and 3, called 911 about 9:30 a.m. Saturday after discovering their bodies in the Reseda, Calif., apartment, the Los Angeles Times reported. By then, Carrillo was gone.

Police did not disclose a cause of death, although multiple local outlets reported that the children had been stabbed. Authorities have not yet identified a motive, and Lt. Raul Jovel told reporters that investigators would be “talking with this lady at length to try to figure out what’s going on in her mind.”

“These are the moments we carry throughout our career,” he said. “It’s hard to process that as a police officer.”

Teri Miller, who said she is a cousin of the children’s father, told Fox 11 that Carrillo had been “very sick” and “not herself” for several months. She said the father, identified as Erik Denton, had been seeking help through police and Child Protective Services.

Miller said Carrillo had left with the children in February.

“He did everything that he could think of to get his kids back home safely and to get her help, too, because he still loved her. But she was just not herself,” she said. “So he’s also frustrated with the system because the system failed them. The system failed these kids.”

She described Denton as shocked and devastated. He had been planning to take the kids to buy fish for their new fish tank on Sunday, she said.

After pronouncing the children dead at the scene on Saturday, police asked for the public’s help in finding their mother. They reported that Carrillo was believed to be driving a silver Toyota pickup they said she had carjacked in the Bakersfield area.

Hours later, she was taken into custody. She had not been booked into jail as of Sunday afternoon, according to the Los Angeles County Sheriff Department’s online booking system, and it was not immediately clear whether she had an attorney.

“She did a horrific crime here,” Los Angeles Police Lt. Ben Fernandes said outside the Reseda apartment complex, “then followed it up by another crime north of here. And it’s those behaviors that ultimately got her caught.”

Authorities remained at the complex after dark on Saturday, with yellow police tape stretched in front of the building. Stunned neighbors gathered outside. Some left candles and toys in a small memorial near the front door.

Elizabeth Cuevas, who lives in an apartment above the one where the crime occurred, told the Los Angeles Times that she had met one of the three children. The soft-spoken, “sweet little girl” had asked to pet her Chihuahua mix, she said.

“She was a perfect little angel,” Cuevas said. “She was precious beyond what you could imagine.”

She added: “An angel shouldn’t have to go that way.”

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