Durham Constabulary said on Saturday that police officers and mountain rescue teams focused their search in Hamsterley Forest and the surrounding areas, where there are a number of running trails.
Chief Inspector Dean Haythornthwaite, of Durham Constabulary, previously said: “We have become increasingly concerned for Jenny since she was reported missing on Tuesday and have been exploring all lines of inquiry.”.
Jenny Hall, 23, was last seen leaving her home in Tow Law, County Durham, just after 3pm on Tuesday.
Digital intelligence officers have checked Ms Hall’s mobile phone, smartwatch and running apps, but have found no leads.
Specialist drones have been used in the major search for a young runner who has been missing for four days.
