Mr Dorey is on exchange from the University of the West of England
A man fitting the description of missing Guernsey student Jonathan Dorey was seen swimming in a US river on the day he went missing in the country.
The 22-year-old, known as Jonny, is an exchange geography student at the Virginia Commonwealth University and was last on 2 March.
Police said despite the witness report Mr Dorey was still a missing person and searches for him were continuing.
Some of his personal items were found next to the James River last month.
A major search operation has been in place for the past five weeks since he went missing with his mountain bike.
Members of Mr Dorey's family, who have returned to Guernsey from America, have thanked everyone for their ongoing support and prayers.