POLICE investigating a degrading sex attack on a 17-year-old student have traced a couple who could hold vital information.

But they are still seeking other people who were in New Elvet, Durham City, late last Thursday night when the slightly-built victim, who is studying at a college on the city's outskirts, was set on by three young men.

"The first couple we wanted to speak to came forward immediately after we put out our media appeal. But we still haven't traced the others and we would like them to come forward," said a police spokesman.

Detectives are seeking two men and a woman, possibly students, who were also walking along New Elvet in the opposite direction to the victim.

They also want to hear from a man and a woman who called at the police station at about midnight to produce driving documents.

The attack happened at about 11.25pm. The victim had walked from the North Road area on her way to her college.

Closed-circuit television cameras confirmed the girl, who was wearing a white T-shirt and jeans and white shoes, had walked up New Elvet. As she approached a set of traffic lights she was taunted by a group of men.

They were carrying what were believed to be sticks and were engaged in a mock sword fight as she approached.

In the skirmish that followed, the victim was struck on the head and lost consciousness.

When she regained consciousness she was lying on a secluded grass area, where she was pinned down by her assailants and was struck again.

Investigators believe the girl may have been dragged or carried from the street to where the sex attack was carried out.

The incident happened near Dunelm House, the Durham Students' Union building, and union president Tom Page said police had examined the building's security TV footage for clues.

Mr Page said: "We are concerned because it was outside our building and we want to assist. It is unusual for something like this to happen where it did."

He said that the Students' Union and the university were running a routine campaign to raise awareness of personal safety and security.

Anyone with information is asked to call Durham City police station on (0191) 386 4222 or call Crimestoppers on 0800 555 111.