Christina Molloy, who murdered a 70-year-old woman with a friend in 1992, has died.
She and Maria Rossi were both 17 when they strangled and stabbed Rossi's neighbour Edna Phillips in Penywaun, near Aberdare.
The judge at their trial in 1993 described the pair as "evil products of a modern age".
Molloy was found at her house in Cambridgeshire, where she had lived following her release from prison.
Cambridgeshire Police confirmed they were called after a woman in her 40s was found at a property.
They said the death was being treated as non-suspicious and have passed the case to the coroner's office.