DETECTIVES have revealed new evidence as they continue their investigation into the disappearance and murder of Sally Ann John.

Sally went missing on September 8, 1995, from the Station Road junction with Aylesbury Street and Alexandra Road.

She was just 23 when she vanished. Her body has never been found.

Sally's disappearance was initially treated as a missing person enquiry as there was nothing to suggest anything untoward had occured.

But when detectives revisited the case as part of a review in 2014 they could find no evidence that she was still alive and a murder investigation was launched.

Last night, officers from the Major Crime Investigation Team used an appearance on the BBC's Crimewatch programme to renew their appeal for information and to reveal, for the first time, a crucial piece of evidence.

A handwriting expert has determined that a postcard, which at first glance appeared to have been sent by Sally Ann to a male friend in Swindon three weeks after her disappearance, was almost certainly not written by her.

Now detectives say that finding the person responsible for writing the postcard has become a top priority for detectives.

The postcard, which is marked "2 Oct 1995", was sent to someone known only as "Clive" and purports to be from Miss John, who says she is living in London.

It says: "Dear Clive,

"Thought I'd write as I heard you've been missing me and that you were rather worried that something had happened to me. As you can see I'm in London now. But no one compares to you Big Boy.

"Love Sally xxxxxx"

The night Miss John disappeared she had been working on the streets between the bus station and train station in central Swindon. She was last seen at around 10.50pm on Alexandra Street.

Her disappearance was initially treated as a missing person's inquiry but police launched a murder investigation in 2014. Her body has never been found.

The following year Wiltshire Police began forensically searching her former home, a flat in Kimmeridge Close in Nythe, Swindon. Three men were arrested on suspicion of kidnap and murder and later bailed.

Wiltshire Police is offering a cash reward of up to £25,000 to anyone who can provide them with information that either leads to the discovery of her body, or to the succesful conviction of a person or persons for her murder.

Detective Sergeant Don Pocock, of the Brunel Major Crime Investigation Team, said: “We hope that the appeal on Crimewatch will encourage anyone who may have known Sally all those years ago and has information they have not yet reported to police, to get in touch.

“The writing on the postcard, which claimed to be from Sally, suggested that she was alive and living in London when it was sent not long after she disappeared in 1995.

"However, handwriting experts have thoroughly analysed the card alongside Sally’s handwriting from her personal address book, and have concluded that the postcard was written by someone other than Sally.

“It has been nearly 22 years since Sally disappeared - I appreciate this is a long time and no doubt friendships, relationships and lives will have changed dramatically since then. But if you have any information about what happened to Sally, it could be the missing piece in our jigsaw.

“Sally’s family are understandably desperate to know what happened to their daughter and we are doing all that we can to ensure they have some kind of closure.

“We are offering up to £25,000 cash reward to anyone who can provide us with information which will lead to the discovery of Sally’s remains, or anyone who can provide us with information which secures a conviction at court in relation to those responsible for her murder.”

Anyone with information should call the force non-emergency line on 101.