A driver who captured dashcam footage of Jenny's abandoned car later told of his increasing fears for the woman who went missing in "an incredibly remote area".
As the search ramps up, here are the five biggest clues in the search for the missing jogger who vanished on a remote moor.
Chief Inspector Dean Haythornthwaite, of Durham Constabulary, added: "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.
Teesdale and Weardale Search and Mountain Rescue Team (TWSMRT) said it scoured an area of moorland between Eggleston and Stanhope on Wednesday.
It emerged earlier this week that Jenny had parked her car in a remote lay-by surrounded by empty moorland before she went missing.
