Detectives are investigating the rape of a teenage girl on a lane behind a Swansea industrial estate.
Police have appealed for potential witnesses to come forward
The teenager said the attack happened on land near Cwmdu industrial estate in the city about two weeks ago.
South Wales Police say they are looking for a "stocky and muscular" man aged in his late 20s.
They also want to speak to a man with a dog who stopped to ask the victim if she was ok because he may have seen the attacker run away from the scene.
Swansea CID said they were investigating an allegation of rape on a "young female" adding that the attack took place at about 1945 BST some time between Monday, 15 May and Thursday, 18 May.
The attack is reported to have happened on a lane running behind houses on Bryngolau at its junction with Brickyard Road.
The lane leads to rough ground to the rear of Cwmdu industrial estate.
Police described the attacker as in his late 20s, about 6ft 3ins tall with a stocky and muscular build.
He had short black hair, a pock-marked face and was wearing a black zip-up jacket and jeans.
DCI Peter Azzopardi, of South Wales Police, said he wanted to speak to a man with a dog who stopped his car to ask if the victim was ok.
He said: "I am making an urgent appeal for this male to make himself known to the police as he may be a significant witness within this investigation."
He added: "Allegations of rape are treated with a great degree of urgency and a full investigation is being carried out."
Anyone with information can contact Swansea CID on 01792 456999 or Crimestoppers on 0800 555111.