Merseyside Police are appealing for anyone with information or sightings of missing student Adam Seaton to come forward.
It is more than three weeks since 20-year-old Adam went missing from his home in Marshside.
Together with colleagues from the Coastguard and Mersey Fire and Rescue Service extensive open land searches have been carried out in the Sefton area and CCTV, mobile phone and other enquiries have taken place.
Adam, a geography student at Edge Hill University, went missing from his home address in Melrose Avenue, on Thursday 9 August. He visited the Lake District several times a year with friends.
When last seen Adam, who is 6ft 2in tall, of slim build with brown hair and brown eyes, was wearing a burgundy tracksuit top, black and white T-shirt, blue jeans and burgundy Puma trainers.
Detective Chief Inspector Gayle Rooney said: “Three weeks ago today Adam went missing from his family home and there have been no confirmed sightings of him since.
“His family are naturally very concerned for his welfare and are desperate for information as to his whereabouts.
“It is thought that Adam may have driven his mum’s red Ford Fiesta car to the RSPB car park on Marshside/Marine Drive on Thursday 9th August and I would ask anyone who was in the vicinity of that car park, or who has captured footage of the car Adam was driving, to get in touch as they may have vital information.
“A lot of people have been out and about searching for Adam around the marshlands area where the car was seen.
“While I know Adam’s family are very grateful for their assistance I would remind people that a lot of the surrounding area is inaccessible and I would advise them to urge caution and check with the coastguard before attempting to go out around that area.”
Anyone who has seen Adam or knows of his whereabouts is asked to DM @MerPolCC, call 101 or contact Missing People on 116 000.