Police in Nottingham have been questioning early morning commuters in the city exactly a week after a man was the victim of a group sex attack.
The man was sexually assaulted by several men who approached him at the junction of Castle Boulevard and Cecil Street at 0540 BST on 6 April.
Police said the victim has been left traumatised and want to speak to anyone who may have witnessed the attack.
A man in his 20s has been arrested and bailed by Nottinghamshire Police.
Det Ch Insp Kate Meynall said: "This is a very serious offence. The effect it has had on the victim is massive.
"This is a man who was walking home alone, who has been approached by a group of men who have attacked him.
"It was a very traumatic event and we need to make sure we bring these people to justice."
The group of men are described as white, in their late teens or 20s and wearing casual clothes, police said.