A 19-year-old woman was raped by a man she met at a party in Manchester.
Police said the woman had been drinking at a house in Baguley, when a man made advances towards her.
She refused and went to bed, but in the early hours of the next day he woke her up and raped her. She managed to fight him off and he fled.
Detectives have released a photograph of a man they want to speak to over the attack, which happened on 22 June.
The man is described as being in his mid-20s, 5ft 7in (1.7m) and of a skinny build.
He was wearing a black T-shirt and wore a rusty silver chain.
Det Con Mark Atkinson said: "This young woman has been through a traumatic ordeal and deserves the peace of mind of seeing her attacker caught.
"I would ask people to look carefully at the picture we have released and if you do know this man, or you think you recognise him, please do the right thing and call us immediately.
"Your information could be absolutely vital to helping us find this man and at least giving the young woman the chance to start to rebuild her life."