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 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.”

Mansfield was jailed a minimum of 30 years after pleading guilty to murdering Ms Alfanso in August 2006.

She had been stabbed about 20 times in the head and neck.

A post-mortem examination found she had 97 wounds, bruises and cuts on her body as a result of the attack.