Liliana Carrillo, 30, is the lone suspect in the deaths, LAPD officials said at a news conference.
The children were 3, 2 and 6 months old, said Lieutenant Anthony Cato.
A law enforcement source told CNN the three had been stabbed. The police did not disclose the cause of death.
A police report was not readily available and it is not known whether Carrillo has a lawyer.
The suspect’s mother discovered the children in the Reseda neighborhood, Lieutenant Raul Jovel said.
West Valley Patrol Officers responded to a call about “a possible death” in apartments there Saturday morning and found the children, LAPD said in a tweetCarrillo was taken into custody in Tulare County, in the Ponderosa community, the department said. Tulare County is located approximately 160 miles north of the Reseda neighborhood of LA.
Officials did not mention a possible motive.
Carrillo is also suspected of carjacking a silver Toyota pickup in the Bakersfield area, the LAPD said in a tweet during the search for her.