The grandmother of three young murder victims discovers the bodies.
A woman is being held on suspicion of killing her three daughters.
The youngest one was 2 months old.
When sheriff's deputies arrived at the home of 30-year-old Carol Coronado Tuesday, they found the baby and a 3-year-old and 2-year-old girl dead.
A neighbor says Coronado's mother discovered her daughter and the children in a pool of blood on a bed in Los Angeles County.