Detectives probing a 23-year murder mystery think they have found the killer’s DNA on a rope used to tie up the body.
They also believe another person may have helped dump Melanie Hall’s remains on a motorway slip road.
She was last seen at a nightclub in Bath, Somerset, in June, 1996.
Her body – wrapped in bin liners and bound with distinctive blue rope – was found in undergrowth 13 years later by men cutting grass alongside the M5.
Det Chief Insp James Riccio said the DNA investigation was in its “embryonic stages” but added: “We’re confident that, with corroborative evidence, it will lead to a charge.”
He also revealed that the person who dumped the body “in haste” may not have been the killer. He said: “People know how Melanie got here. People know how she died.”
And in a direct appeal for any accomplice to come forward, he went on: “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.”
Police want to highlight the kind of 4mm blue polypropylene rope on which they found the DNA.
It’s commonly used on building sites and for drawing electrical cable through trunking.
Det Chief Insp Riccio said a 13-metre length was found at the scene alongside the M5 near Thornbury, Glos.
He said: “It was made up from four lengths knotted together. In addition to the three knots joining the ropes, there were four others – a total of seven.”
There have been 11 arrests since hospital worker Melanie disappeared but nobody has been charged.
Police have had 1,751 calls about the case and taken 1,668 statements.
Melanie’s dad Steve said: "Police have poured endless resources into their attempt to find her killer.
“Sadly, as yet, this objective remains unfulfilled although my family and I remain eternally optimistic that eventually they will be successful.
“In our family we will forever grieve for and miss our lovely daughter.
“Her mother’s lasting memory is the day she viewed a battered skull and a few broken bones in the coroner’s office”
Melanie’s parents have reinstated a £50,000 reward for information leading to the killer’s conviction.
Crimestoppers has also reinstated a reward of up to £10,000.
