Murder investigation launched as man dies after prison attackA man in his 20s has been arrested on suspicion of murder. View Image The man died after an attack at HMP Highpoint Prison (Image: © SWNS Group)A murder investigation has been launched after a man died following an attack at a prison. The man had been an inmate at HMP Highpoint Prison in Stradishall in Suffolk. The incident is being treated as a murder investigation. The police are working closely with HMP Highpoint to investigate the full circumstances of the incident.