On the night of Thursday, December 13, detectives were retracing the steps of a 19 year-old woman after she was sexually assaulted in a dark Melksham alleyway.

Plain-clothed detectives joined uniformed officers in Melksham to question clubbers about the sex attack, which has left town residents shocked.

Police said the victim is traumatised and deeply upset after the 20 minute ordeal, which happened in a dark alleyway off Ruskin Avenue near Clackers Brook.

House-to-house inquiries and security camera footage have failed to throw up positive leads, forcing police to retrace the victim's steps in the hope of catching the attacker. The victim's clothes have been sent for forensic analysis to trace DNA evidence.

Melksham mayor Vic Oakman said people are now afraid to take their children to the nearby play park until the attacker is caught.

He said: "I was absolutely shocked and mortified. I still cannot believe this sort of assault can happen in Melksham. It is a very dark area with no lighting and is not safe to walk down at night.

"Lots of children use the park and mothers have said to me they will not let them again until this man is caught. You don't know who he will go for next and how far he will actually go to get what he desires."

The victim was out drinking with friends in Melksham on Thursday night and is believed to have left Buds Bar in Lowbourne at around 2am.

She was approached from behind by a stranger at around 2.40am, 40 yards past the Army Cadet hut in Ruskin Avenue. The route is a popular one for walkers cutting through Lowbourne to the Queensway estate but no witnesses have so far come forward.

Insp Neil Bagnall, of Melksham police, said detectives would continue with their inquiries. He said: "A sex offence is a serious offence. This man is someone's son, brother or friend and they should let us know if they suspect anything at all. It is a horrendous crime and I couldn't imagine the trauma she suffered. My advice is for people to keep to well-lit areas and not to walk home on their own."

Police are planning to release a photo-fit of the attacker.

The attacker is described by the victim as being in his late 20s, white, clean-shaven, muscular with a medium build, 6ft tall, with thick eyebrows which joined in the middle. He was wearing a round necked, close-fitting dark t-shirt, a black baseball cap and close-fitting trousers.

Anyone with information should call DC Andrew Cross on 01225-763101 or Crimestoppers on 0800 555111.