A Prison Service spokeswoman said: "An incident at HMP Long Lartin on Thursday February 14 resulted in the death of prisoner Subhan Anwar.
"Two prisoners are now in police custody and the matter is being investigated by police."
More top news
Kenneth Wilson, 49, is wanted in connection with numerous offences including stalking and harassment committed in July against one woman.
Mrs Maguire, a schoolteacher in Leeds, was stabbed seven times by pupil Will Cornick in April 2014, and died in hospital later.
Motorists are being asked to avoid areas of Craven due to heavy flooding.