POLICE have issued a picture of the Gurkha knife a sex fiend held to the throat of a 17-year-old girl as he raped her in a country park.

Detectives hope that the photograph of the distinctive weapon will help them track down the man who attacked the teenager as she walked her dog through Moses Gate Country Park a week ago today.

Today the police chief leading the hunt declared: "Someone somewhere will know who has committed this Crime."

The 14 inch-long knife, also known as a 'Khukuri', is the legendary blade of the famous Nepalese Gurkha soldiers.

It was recovered by police near the area of woodland where the teenager was assaulted after being attacked from behind and dragged into undergrowth. It has a highly distinctive blade featuring a carved design, a brass hilt and a wooden handle with metal inserts.

As forensic experts examined it today, police said they hoped someone would recognise the knife and contact them. They appealed to anyone who may own one like it to check whether it is still there. Det Insp Andy Aston said the response from the public had already been tremendous.

Information gathered from more than 40 calls is being investigated and police are probing new leads. Posters appealing for information -- including an e-fit image of the rapist -- are on display across Bolton.

Det Insp Aston said: "Somebody must know where this knife has come from. It is very distinctive. I want people to look at this picture and contact us. If you own a knife like this, is it still where it should be? Has it been stolen? Or do you know someone who owns a knife identical to this one? Our fear is that this man could strike again." The teenage victim has been left severely traumatised by the attack.

She was grabbed as she walked along a foot path, ordered to strip naked and then raped.

Her ordeal at about 2pm last Tuesday lasted for 15 minutes before she managed to break free. She ran naked through the River Croal before raising the alarm with a passer-by. Detectives have urged women to avoid secluded areas. Det Insp Aston said: "If you know this man, then give him up."

The Farnworth victim has received counselling from officers and helped them to compile the e-fit image. Anyone with any information is asked to contact Farnworth CID on 0161 856 5853 or Crimestoppers on 0800 555 111.