A woman of 21 was raped in the Elm Grove area of Brighton in the early hours of Friday (1 April) after a boozy night out.
She had been in Vodka Revolution in West Street and stopped at a fish and chip shop on her way to a seafront taxi rank.
She took a cab with the suspect at about 2am from outside the Old Ship Hotel in King’s Road.
They went to a property in the Hanover area where the victim was raped.
Detective Constable Rex Petty said: “The victim is being offered our full support during this investigation.
“Police are carrying out forensic examinations, viewing CCTV and house-to-house inquiries are continuing.
“I am keen to trace the taxi driver who picked the victim and suspect up outside the Old Ship Hotel and anyone who may have seen them prior to this, as they may hold information key to this investigation.”
The suspect was described as black, with long dreadlocked hair and a beard, wearing a red top, dark jacket and dark jeans.
He was seen holding the victim up as she walked.
Anyone with information is asked to contact Sussex Police on 0845 6070999 or to call the independent charity Crimestoppers anonymously on 0800 555111.