Northumbria Police have released another picture of Newcastle University student Jason Fyles who went missing early on Thursday May 16.
They also want to contact a man who spoke to Jason the night he disappeared.
Superintendent Andy McDyer said: "We know that Jason spoke to this man before going into his friends' house and we believe that he may have information that would help us to understand Jason's state of mind at the time.
"This was not the last sighting of Jason, but speaking to him will help us to build a picture of Jason's movements before he went missing.
"We are carrying out extensive enquiries to trace Jason's whereabouts and we are appealing for anyone who thinks they may have seen him since last Thursday to contact us."