Police investigating the murder of Melanie Hall have issued a renewed public appeal for information to mark the 11th anniversary of her remains being discovered.

The 25-year-old was last seen at Cadillacs nightclub in Bath in the early hours of June 9 1996 following a night out with friends.

The last sighting of Miss Hall, a clerical worker at the Royal United Hospital in Bath, was inside the nightclub in Walcot Street at about 1.45am.

On October 5 2009, workmen found her remains next to the northbound sliproad at junction 14 of the M5 motorway.

Her parents are offering a £50,000 reward for information leading to the arrest and conviction of the person or people responsible for her murder, with a £10,000 reward also available through Crimestoppers.

Avon and Somerset Police have reissued an e-fit first publicised as part of an appeal in 1996 to identify a man who two witnesses said they saw with a woman matching Miss Hall’s description inside the nightclub.

Detectives are also asking for anyone with information about a sighting of a woman arguing with a man in the Old Orchard – close to the nightclub entrance – between 1.45am and 2am on June 9 to come forward.

They say they have “not ruled out” that the woman seen arguing with the man could have been Miss Hall.

Detective Superintendent James Riccio, of Avon and Somerset Police, said officers remain “as determined as ever” to find out who murdered Miss Hall and why.

“We have a number of active lines of inquiry we’re pursuing, including reviewing a vast amount of material gathered during what’s been one of the biggest investigations ever carried out by Avon and Somerset Police,” he said.

“An e-fit was released as part of a public appeal in 1996 of a man seen inside Cadillacs nightclub with a woman matching Melanie’s description – we’d still like to hear from anyone who recognises the man in the image, or thinks they know who it is.

“In addition, we’d like information about an unconfirmed sighting of a woman potentially matching Melanie’s description who was engaged in an argument with a man in Old Orchard, around the corner from the nightclub entrance, between 1.45am and 2am.

“We don’t know whether this was Melanie, so if anyone has further details which could help on this aspect, please call us.

“A small or seemingly insignificant piece of information could still be the key to solving this case.

“We’d ask the public to please consider the appeal points above, as well as the key dates and locations which feature in this case, and call our investigation team if you can help.

“You may feel able to speak to us now when you couldn’t before.”

Police are also appealing for anyone who was in Cadillacs nightclub on the night Miss Hall went missing to come forward.

Anyone who saw suspicious activity or a vehicle parked on the northbound sliproad at junction 14 of the M5 at Thornbury in the early hours of June 9 or the days afterwards should also contact police.

Miss Hall’s clothing – a pale blue silk dress, black suede mule shoes, a cream single-breasted long-sleeved jacket and a black satchel-type handbag – have never been found.

Cosmetics and a Midland chequebook and bank card belonging to Miss Hall, as well as items of jewellery including a Next watch and silver drop earrings, have also not been located.

Last year, Miss Hall’s father, Steve Hall, said the family remain “eternally optimistic” that police will identify who killed her.

“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,” Mr Hall said.

“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.”

– Anyone with information should contact Avon and Somerset Police on 101 and inform the call handler that they are calling about the Major Crime Investigation Team’s Operation Denmark inquiry.