An urgent search is currently underway in Teeside in the hunt for a missing runner, after her vehicle was found abandoned on the roadside.
Jenny Hall, 23, was last seen leaving her home in Barracks Farm, Tow Law, shortly after 3pm on Tuesday.
In an update on Friday, Durham Constabulary said her last known location was on the B6278 between Stanhope and Eggleston – where her red Ford Focus was parked.
Police are now using specialist drones to search for Hall – and have asked volunteers not to join.
Officers are now saying they are becoming "increasingly concerned" for her safety, with the runner described as a white female, 6-foot tall and has dark brown hair.
Several expert mountain rescue search teams and air support have joined the operation, with police dogs and mountain rescue teams searching for a missing runner in County Durham.
Durham Police said it would be working in Hamsterley Forest and the surrounding areas, where "Jenny likes to run through".
Digital intelligence officers have also conducted enquiries on Ms Hall's mobile phone, smart watch and running apps, with the hope they may reveal her location.
However, the force has said "none have yielded any results unfortunately".
Police say the search continues despite the "challenging weather conditions and terrain".
Teeside and Wearside Police are searching a 100 mile area for any sign of the runner, with the local community out in force as they attempt to locate her.
In a statement posted to facebook, Durham Constabulary said: "A major search continues today for missing Jenny Hall.
Specialised sniffer dogs are being used in the area around Jenny's last known location where her car was parked, on the B6278 between Stanhope and Eggleston.
"The search today is concentrating on running trails Jenny frequently uses between Eggleston and Hamsterley.
The force added: "Her family have now confirmed she may have also been carrying a green jacket and had her hair up in a ponytail.
Chief Inspector Dean Haythornthwaite, of Durham Constabulary, said: “We have become increasingly concerned for Jenny since she was reported missing on Tuesday and have been exploring all lines of enquiry, including dozens from members of the public.
“We are focussing our search on areas we know Jenny likes to run through and we are determined to do everything we can to find her.
“I would like to thank everyone who is working around-the-clock in our search and efforts to reunite Jenny with her family.”
Anyone who believes they may have seen Jenny or has any relevant information about her whereabouts is asked to contact police immediately on 999.
