North Yorkshire Police are appealing for information about Kieran Chapman, 38, who is believed to be missing.
Mr Chapman’s apparently abandoned car was reported to the police by a member of the public on December 2.
The car was parked in the area of Harwood Dale within the North York Moors National Park near Scarborough, and may have already been there for several days.
From the location of the car, it is thought that Mr Chapman, a keen walker, may possibly have gone hiking on the Moors, however no sightings of him have yet been reported.
On December 3 North Yorkshire Police called in Scarborough and Ryedale Mountain Rescue to assist officers in the search for Mr Chapman, however nothing was found and the search was stood down after three days.
Police are now continuing their enquiries with family and friends of Mr Chapman, in an effort to discover his movements and his possible location.
Inspector Matthew Millington of North Yorkshire Police believes that the public may also be able to provide vital information to assist with the search.
He said: “We are trying to establish when Mr Chapman was last seen, and we are appealing for the public to help. We believe he may have parked his car, a red Volkswagen Polo, at Harwood Dale sometime in the last few days of November or very early December.
“If anyone remembers seeing a man in this car around this time, and can give any information about what he was wearing or which direction he was heading, we would like to hear from them.
“At this point we do not know for certain that Mr Chapman has come to any harm, and we very much hope that he may still be found safe and well.
“However it has been a number of days since he has been seen, and his family are obviously increasingly concerned. If he is out there, we would urge him to contact the police and let us know he is safe.
“Meanwhile, if anyone has any information that could be helpful to us, or any information about his whereabouts, please call us on 101.”
If you have information that could help the police to track Kieran Chapman, please call North Yorkshire Police on 101.