Detectives also want anyone who recognises him to reach out to police.
In the early hours of Monday 9 February 2015, a 20-year-old woman was out with friends in the city centre when she started talking to a man.
They agreed, along with her friends, to go back to a flat in the student village to carry on drinking.
Once her friends had gone to bed, the woman was raped.
Now police are eager to speak to a man who may have information as to what happened.
Detective Constable Sophie Swift said: “We have been investigating this case for over a month and unfortunately our lines of enquiry have come back with no answers.
“I am keen to speak to the man in the image and would ask him to get in contact with us as soon as possible.
“I would also urge anyone who may recognise him or know him to call police.”
Anyone with information should phone police on 0161 856 2262 or the independent charity Crimestoppers, anonymously, on 0800 555 111.
