Peter Maine inquiry: Further potential witnesses sought
Officers investigating the death of a solicitor have appealed for a number of people spotted in the area where his body was discovered to come forward.
Peter Maine, 56, from Wynyard, Stockton, was found with stab wounds on the outskirts of Durham on 1 September.
His death is continuing to be treated as "unexplained and suspicious".
CCTV footage has been released in a bid to trace a couple police believe might have important information.
They are shown walking on North Bank towards Baths Bridge from the direction of the city.
The man was wearing a dark long-sleeved top and dark trousers, and the woman had dark trousers and a red long-sleeved top.'Vital information'
Det Insp Lyn Peart, of Durham Police, said: "We know this couple walked along towards where Mr Maine was found and left the Maiden Castle area as the ambulance arrived.
"We are yet to speak to this couple and would encourage them to contact us."
Mr Maine's body was discovered, wearing running kit, near the track at Maiden Castle's sports centre at about 08:00 BST.
Other potential witnesses include a runner near the Maiden Castle car park seen at about 08:15 BST, who had two black Labrador-sized dogs running alongside him.
Officers also want to speak to a cyclist who arrived in the Maiden Castle area at about 08:10 BST before riding over the bridge on to the playing fields, and a man walking on the Sherburn side of the river in the direction of Shincliffe at around 07.50 BST.
Det Insp Lyn Peart said: "We would urge these people to come forward as we believe they may hold vital information which could assist us in our investigation."