Fresh CCTV images have been released of a teenager, who is feared to be walking 280 miles to be with his girlfriend during the coronavirus lockdown.
Owen Harding has not been seen since he left his home at around 6pm on Thursday March 26.
A desperate search was launched by the 16-year-old's family and friends with Sussex Police involved.
As part of their enquiries, officers have formed a timeline of Owen's suspected movements immediately after he left the family home in Saltdean, East Sussex.
A photo emerged of a person similar to Owen's description walking past a house in Bevendean Avenue at 6.08pm that Thursday.
Two witnesses have also reported seeing a boy matching Owen's description walking alongside the A259 coastal road between 6.15pm and 6.30pm.
Police are appealing for anyone driving along this clifftop A-road with a dashcam to come forward in the hope of discovering where he went from there.
Another CCTV photo appeared to show Owen walking south in nearby Bannings Vale at around 6.50pm and possibly turning into Hamsey Road.
His girlfriend of two years Meg Rhodes, 16, from Pocklington, East Yorkshire, has reportedly pleaded for him to return home.
She believes he took the travel restrictions imposed by Covid-19 hard and could be travelling to see her on-foot as he couldn't get a train.
Owen's mum Stella Harding also said her son was upset at the prospect of not being able to see his long-distance girlfriend for an indeterminable time due to the coronavirus lockdown.
The desperate search to find the youngster has been backed by YouTuber Pewdiepie, radio host Zoe Ball and Loose Women star Nadia Sawalha, whose daughter is a close friend of the teenager.
Investigating officer Detective Chief Inspector Alasdair Henry said: "It's now been a week since Owen’s disappearance and we share the concern of his family and friends for his safety and welfare.
"Searches have been taking place in the Saltdean and Telscombe Cliffs area and there have been extensive enquiries locally.
"We are aware of his connection to Yorkshire and suggestions that he may have set out to walk there to see his girlfriend.
"We have not discounted this, but there are no indications at all to support this or indeed that he has left Sussex.
"We would like to thank the public for their support in our investigation and while we appreciate people would like to help with our searches, we are urging everyone to abide by Government guidance at all times.
"We are utilising all of our available resources to search locally and will, of course, link up with colleagues across the country if there is anything to suggest that he has travelled out of Sussex.
"We are very keen to hear from anyone who can help us in our search for him.
"This may be through dashcam footage, local CCTV along the A259 between Newhaven and Brighton, by identifying the person in Bevendean Avenue or anything else, no matter how small you think that might be, that might lead to his safe return."
Owen is described as white, 5ft 11 in to 6ft tall, of athletic build with short brown hair.
He usually wears white trainers and a dark hoodie but is thought to wearing dark jogging bottoms.
Anyone who sees Owen is asked to dial 999 immediately.
To report a sighting of him or if you know of his whereabouts, report online or call 101 quoting Operation Chartwell.
