Yates was born in 1964 in Houston and worked as a nurse. She and her husband had five children between 1994 and 2000: Noah, John, Paul, Luke and Mary. She had a documented history of severe postpartum psychosis, with two suicide attempts, hospital admissions, and a psychiatrist's explicit warning that she should not have another child. She was taken off the antipsychotic medication that had stabilised her weeks before the killings.
On June 20, 2001 she drowned all five children in the bath, one after another, and then telephoned the police and her husband. She believed, and told doctors afterwards, that she was damned and that killing them was the only way to save their souls.
She was tried in Houston in 2002. The defence and the prosecution both accepted that she was mentally ill; the question was whether she knew that what she did was wrong, which is the Texas test. The jury convicted her of capital murder and she was sentenced to life with parole eligibility at forty years.
On January 6, 2005 the Texas Court of Appeals overturned the conviction. Park Dietz, the prosecution's psychiatric expert, had testified that an episode of the television series Law and Order had shown a woman drowning her children and being acquitted on insanity grounds, implying she had copied it. No such episode existed. The court held that the false testimony could have affected the verdict.
At the retrial in July 2006 she was found not guilty by reason of insanity and committed to a state mental hospital, where she remains. Her husband divorced her in 2005.
The case changed public and professional discussion of postpartum psychosis in the United States more than any other, and it is in the archive as a single act rather than a series. The record here is unusually complete, and it shows a woman whose illness was known, documented and warned about before any of it happened.