Andrea Shaw, a 23-year-old from Payette, Idaho, is indicted on two counts of first-degree murder for the deaths of her 18-month-old twin toddlers, Tyson and Dallas. According to reporting, the children were found dead in a shared bed on 1 May last year. Authorities allege Shaw suffocated them.

Shaw has said the twins died after receiving routine vaccinations. Sources note she made that claim in the aftermath of the deaths and that a lawsuit tied to Children’s Health Defense—an anti-vaccine organization founded by Robert F. Kennedy Jr.—has argued that vaccines caused the children’s deaths.

Doctors who reviewed details of the case at the request of The Guardian say the proposed link between vaccination and the deaths is not medically possible based on known vaccine effects. Other outlets report that the indictment is based on the grand jury’s determination of probable cause, and that Shaw faces trial under the murder charges. The case involves a dispute between the mother’s assertions and medical assessments cited by media outlets.