They are trying to trace the man after a 21-year-old female student was attacked in the early hours of the morning at the Bradford University complex.
The suspect was also caught on CCTV, police said.
The student was on her way home at around 1am on May 14 when she was grabbed by the wrists and sexually assault by a male suspect.
She managed to get away after punching him in the chest and he fled the scene.
The suspect is described as an Asian male in his 20s, 5ft 6in tall, with a short trimmed beard. He was wearing a black t-shirt with the words ‘Toyko NYC and Paris’ emblazoned on his chest and a hooded top.
Detective Inspector Damian Simpson, of Bradford District Safeguarding, said: “Officers are continuing to support the victim who was understandably extremely distressed by what took place.”
Anyone with information should call police on 101, quoting crime reference 13180230190.