New information has been issued into the death of a woman found near Thornbury.

The remains of Melanie Hall were found next to the junction 14 northbound slip road of the M5 by a workman on October 5, 2009.

Melanie, who was a 25-year-old clerical worker at the Royal United Hospital in Bath, was last seen at 1.10am on Sunday June 9, 1996, sitting on a stool at the edge of the dancefloor in Cadillacs nightclub (now Walcot House) in Walcot Street, Bath, following a night out with friends.

There have been 11 arrests made during the investigation but nobody has ever been charged.

DNA has now been recovered on a length of rope found at the same site as Melanie's body.

Senior Investigating Officer Det Chief Insp James Riccio, of the major crime investigation team at Avon and Somerset Police, said: “As part of a nationwide appeal issued on the 20th anniversary of her disappearance, we confirmed we’d recovered DNA on an item found at the site where Melanie’s body was found.

"Today, we’re confirming the DNA traces were found on a length of blue polypropylene rope which was wrapped around thin black bin liners which had contained her body.

“We recovered a 13-metre length of 4mm rope from the scene, made up from four separate lengths knotted together. In addition to the three knots joining the ropes, there were four other knots on the rope – a total of seven knots.

"It’s commercially manufactured rope and commonly used on building sites and for drawing electrical cable through trunking.

“We believe the choice of deposition site is key. Whoever left Melanie’s body in the undergrowth would have done so in haste. It would have happened on the morning of June 9, 1996, or within a few days of this date.

"It’s likely this person would have then driven onto the northbound M5 and either onto the next junction, or they may have turned off at Michaelwood Services, where they could have used the local road network, including a slip road behind the services, to head back in a southerly direction. We believe it’s highly likely the person who left Melanie’s body at this location was familiar with this area.

“The person who deposited the body may not be the person who killed Melanie. If this is the case, I’m directly appealing to this person to come forward and provide us with information for the sake of Melanie’s family.

"You’ve been living with a dark secret for years but your guilt and fear is nothing compared to the enduring pain felt by Melanie’s family. I want to be clear – our primary focus is on identifying the person or persons who killed Melanie."

Two rewards remain in place for information leading to the arrest and conviction of the person or people responsible for Melanie’s murder. Her parents are offering a reward of £50,000, while a £10,000 reward is also available from Crimestoppers.

Melanie’s father Steve Hall said in a statement: “It is now over 23 years since our youngest daughter, Melanie, was murdered.

"Since that time the Avon and Somerset Police have poured endless resources in their attempt to find her killer. Sadly, as yet, this objective remains unfulfilled, although I and my family remain eternally optimistic that, eventually they will be successful.

“In our family we will forever grieve for, and miss our lovely daughter. A young woman whose life stretched before her until that fateful night in June 1996, when that life was so cruelly snatched from her. She will never fulfil her life’s ambitions, never marry, never have children and my wife and I will never have another grandchild.

"Her mother’s lasting memory of her youngest daughter is the day she viewed a battered skull and a few broken bones in the coroner’s office at Portishead.

“We have little hope that Melanie’s murderer will ever be caught as a result of information from a member of the public. The lives of the person responsible and those others who know what happened that night are governed by a totally different set of rules and moral responsibilities from the rest of us. We are sure that, after all these years they will happily take their awful secret to the grave as we will do the same with our grief.

“For the sake of all those in the Avon and Somerset Police, I hope they are successful in bringing someone to justice, for they have really put up a maximum effort to find Melanie’s killer. Unfortunately, should they be successful, this will not bring closure, as only the return of Melanie alive will achieve that, and that is gone forever.”

The police are seeking answers to the following questions.

Did you own a length, or lengths, of blue polypropylene rope which went missing around June 1996, or do you know someone who possessed rope of this kind, whose behaviour or demeanour may have changed since the summer of 1996?

Were you involved in the aftermath of this crime in any way? Maybe you assisted with the deposition of Melanie’s body but were not involved in the murder. We want to hear from you now.

Did you see Melanie after 1.10am on Sunday 9 June? Did you see her leave the Cadillacs nightclub, or go elsewhere within the nightclub other than sitting by the dancefloor, or see who she was with, at any time after this?

Were you in Cadillacs nightclub that night? It was the evening where England drew 1-1 with Switzerland in the opening game of the football Euro 96 Championships? If you were there and haven’t spoken to police, please call us.

Did you see any suspicious activity or a vehicle parked on the northbound J14 slip road of the M5 at Thornbury in the early hours of Sunday 9 June 1996 or the days immediately afterwards?

Are you concerned about the change in behaviour of a friend or relative, or anyone showing a particular interest in this inquiry?

Do you have information on where Melanie’s clothing or belongings may be? They’ve never been found. They include a pale blue silk dress with a round neck, black suede mule shoes with straps across the front and an open toe, size 5 or 6, a cream single-breasted, long-sleeved jacket and a black satchel-type handbag.

In Melanie’s handbag were cosmetics and a Midland cheque book and bank card. Also missing are items of jewellery including a Next watch with expanding bracelet and silver drop earrings. Where are these items? Have you ever seen them?

You can call the Operation Denmark Incident Room on 01278 648934 or give information online through the Major Incident Public Portal here

Alternatively you can 101 and ask for the Operation Denmark team.

Crimestoppers can be contacted on 0800 555 111. Information can be provided anonymously and they cannot trace your call. You can also visit the Crimestoppers UK website here where information can be provided 100 per cent anonymously.