An Asian mother has been arrested on charges that she murdered her 6-week-old daughter by microwaving her to death

Ka Yang, 29, is being held without bail. The baby, Mirabelle Thao-Lo, was found dead in her home with extensive thermal injuries on March 17, 2011. "She had some really deep tissue burns," Sacramento County coroner's office said. "…It was probably the worst case I've ever seen." Yang initially claimed that her daughter's death was caused by a seizure. The arrest took three months because investigators had to pinpoint what they believed was the cause of death by looking at similar cases. Yang's three young boys, who are all under the age of 7, have since been removed from the home by child welfare workers. Officer Laura Peck said that Yang's motive is unknown. "We wouldn't assess her mental condition," said Peck. "That will be up to the court system. The bottom line is no one knows what happened in that house but her and the little baby."