A serving prisoner has been arrested on suspicion of murder after a convicted killer was found dead 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 his 63-year-old neighbour, Ann Alfanso, at her flat in Whalley Range, Manchester.
Cambridgeshire Police said officers arrested a 44-year-old inmate and a murder investigation was ongoing.
Mansfield was jailed for a minimum of 30 years after pleading guilty to murdering Ms Alfanso, who was found dead by her carer 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.
Ms Alfanso had reduced mobility and was found stabbed about 20 times in the head and neck.
In 2014, Mansfield was given a second life term after stabbing another prisoner with a broken plate at HMP Full Sutton, near York.
Cambridgeshire Police confirmed it was called to HMP Whitemoor when 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.
The death comes after the Ministry of Justice said it would carry out a review following reports that Manchester bomb plotter Hashem Abedi attacked three prison officers at HMP Frankland in County Durham.
The officers suffered life-threatening injuries after they were attacked with hot oil and home-made weapons, according to the trade union covering prison staff.