Doreen Joseph, 83, was jailed last February for eight years and three months after a jury convicted her of nine charges of offences against children.
A spokesman for Peterborough Prison, where Joseph died on Wednesday, said: “As with all deaths in custody, there will be an investigation by the police and the independent Prisons and Probation Ombudsman and therefore we are unable to comment further at this stage.”
A Rushden woman who was last year convicted of sex crimes against children has died in prison.
In court last year, defending Doreen Joseph, Jimmy Vakil said: “It is a more than realistic proposition that she will die in prison.”
while in custody at HMP Peterborough on Wednesday has been named.
He said she suffered from a catalogue of medical conditions.