The 44-year-old was last seen in the Grinton Park Way area of Darlington at about 1.44am last Thursday (May 29).
His gold-coloured 62-plate Honda Civic was later seen at around 8.30pm the same day in the Tindale area.
Durham Police is now urging people to keep a lookout for the car, which has a registration number of OV62 WJZ.
Darren, who has links to the Penshaw and Hylton areas of Sunderland, has been described as 5ft10, shaved head, and may be wearing a blue coat.
He also frequents Hamsterley Forest, Crook, Willington, Bishop Auckland, and Cleveland.
Detective Superintendent Peter Carr said: “We’re really concerned for Darren’s welfare and would urge anyone who has any information on his whereabouts to get in touch.
“Darren drives a distinctive car – if you have seen it, please contact us immediately.”
Sightings should be reported to us on 999, or call 101 if you have any other information that could help the investigation.
Anybody who believes they may have seen Darren, or has any information relating to his whereabouts, to get in touch via 101.
