Four men have been arrested following the death of John Hall.
Police confirmed the local men, two aged 22 and two aged 27, have been arrested on suspicion of assisting an offender and are currently in custody helping police with inquiries.
The body of Mr Hall, 46, from Burn Terrace, Shiney Row, was discovered by a dog walker on Mark’s Lane close to a railway bridge at West Rainton.
A post-mortem concluded that the dad of two died from multiple injuries.
He had been reported missing to Durham Police, although the case has since been taken on by the Northumbria force.
A man who was charged with Mr Hall’s murder was found dead in his prison cell.
Paul Tate, 49, of Silksworth, Sunderland, was one of three men accused of murdering Mr Hall. He was being held on remand at Holme House Prison, Stockton, Teesside and his body was discovered in his cell. A Prison Service spokesperson said: “HMP Holme House prisoner Paul Tate was found unresponsive in his cell by prison staff at 5.45am on Friday 27 September.
“Paramedics attended but he was pronounced dead at 8.26am.
“As with all deaths in custody, the Independent Prisons and Probation Ombudsman will conduct an investigation.”
Mr Tate was jointly charged with Nicholas Rought, 45, of Princess Street, Shiney Row, and Stuart Smith, 42, of no fixed address, with the murder of Mr Hall.