A man is being questioned in relation to an alleged attack in a Swindon alleyway.
But officers are still looking for the woman who reported she had been assaulted.
The victim told a member of the public that she had been attacked in an alley off Manchester Road near Alfred Street at 1am on Sunday.
The man gave chase to her alleged attacker but did not catch him, and when he returned to the woman to see if she was okay she had disappeared.
Police spokeswoman Alvina Kumar said: "From information received we were able to locate the alleged suspect.
"He is a local man who is currently being questioned in relation to the incident.
"We would like to make an urgent appeal for the female victim to come forward."
The woman is believed to be white, and aged in her late teens or early 20s.
Anyone who knows her identity should phone Detective Sergeant James Vaughn of Swindon CID on 01793 528111.
Alternatively, you can call the confidential Crimestoppers number on 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 The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.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