A murder investigation is under way after the death of a convicted killer at a high-security prison.
The body of John Mansfield was found at HMP Whitemoor, near March in Cambridgeshire at about 16:10 BST on Sunday.
Mansfield was jailed for life in 2007 for the murder of Ann Alfanso at her flat in Whalley Range, Manchester.
Cambridgeshire Police said a 44-year-old man had been arrested on suspicion of murder.
The force confirmed it was called to the prison after an inmate in his 60s was found dead.
A Ministry of Justice spokesperson said: “Police are investigating the death of prisoner John Mansfield at HMP Whitemoor on Sunday, 13 April.”
It added the Prison and Probation Ombudsman would also be investigating, as happens with all deaths in custody.
Mansfield was jailed for a minimum of 30 years after pleading guilty to murdering Ms Alfanso, who was stabbed multiple times at her home in August 2006.
A post-mortem examination found she had 97 wounds, bruises and cuts on her body as a result of the attack.
In 2014, Mansfield was given a second life term after stabbing another prisoner with a broken plate at HMP Full Sutton, near York.