Sacramento police have arrested a mother after an investigation found her baby likely died from burns suffered in a microwave oven.
Ka Yang, who is 29, is being held without bail in Sacramento County Jail. She was arrested Tuesday, three months after her 6-week-old daughter was found dead in the family home.
Yang has been charged with homicide, NBC station KCRA TV reported.
Police described the child as suffering "extensive thermal injuries."
Officer Laura Peck said investigators pinpointed what they believe is the cause of death by looking for other cases involving similar injuries.
They found three in the U.S., all after children were burned in a microwave.
Among them was a case involving Dayton, Ohio, woman convicted this year of baking her baby in a microwave. The two other cases were in Galveston, Texas; and New Kent County, Va.
Sacramento County coroner's spokesman Ed Smith told the Sacramento Bee newspaper that the infant's fourth-degree burns were among the worst investigators there had seen.
"The child was apparently killed by the burning of the tissue," Smith told the Bee. "I don't know if they can say how long baby was in the microwave."
Peck says police do not have a motive. No attorney was listed for Yang.
Police said Yang has three other young children, all boys ages 7 and younger. They have been removed from her home.
Last month, an Ohio woman convicted of killing her month-old baby daughter in a microwave oven was spared the death penalty and sentenced to life in prison without parole.
China Arnold, 31, of Dayton, was convicted of aggravated murder. Prosecutors say Arnold intentionally put 28-day-old Paris Talley in a microwave and turned it on after a fight with her boyfriend. The couple had argued over whether the boyfriend was the infant's biological father.