A woman was lifted off the ground and taken into an alleyway by a man who tried to rape her.
The 18-year-old victim was walking in the pedestrianised area of Duke Street, Brighton, when she was attacked at about 6am on November 11.
The woman screamed and the man was disturbed by members of the public who came to her aid.
Detective Constable Vicky Lofts said: "We believe the offender was with another man in the moments before the attack and we are keen to identify both of them.
"We would also like to speak to anyone who was in the area at the time and saw the attack or the aftermath, in particular those who stepped in to help the woman.
"If you saw anything at all, please contact us."
An 18-year-old man from Lancing has been arrested and questioned on suspicion of attempted rape. He was released on bail until January 15.
Anyone with information should email 101@sussex.pnn.police.uk quoting serial 116 of 11/11, call 101 or contact the independent charity Crimestoppers anonymously 0800 555111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article