Detectives in India have reopened an investigation into the disappearance of a Scottish tourist who went missing more than 25 years ago.

Alison Macdonald was 19 when she vanished on August 17, 1981 during a backpacking trip to the Kashmir region.

The case was closed after an initial investigation, but her parents, Kenny and Reta, believe that she may have been kidnapped and have fought for years to discover the truth.

Now it has emerged that police in Kashmir have reopened the inquiry after Interpol asked them to look at the case once again.

The development concerns a recording of an interview with Syed Salahuddin, the leader of the Hizb-ul-Muhajideen militant group which is fighting for Kashmiri independence.

Mr Macdonald, a retired Free Church of Scotland minister, claimed that during the recording, which is thought to have been made in 2001, some of Mr Salahuddin's words were spoken with a Scottish accent.

He said that it could indicate that Mr Salahuddin had been educated by a Scottish person, providing a possible link to Miss Macdonald's disappearance. The recording of Mr Salahuddin has previously been studied by phonetics experts including Professor Michael MacMahon, of Glasgow University, who found no conclusive evidence.

But Mr Macdonald has continued to press police on the issue and detectives in Srinagar, the Kashmiri capital, reopened the inquiry after a request from Interpol.

Yesterday Mr Macdonald, 72, who has been to the region 16 times to carry out his own investigations, welcomed the news.

"It is good news," he said. "Somebody who wasn't able to speak at the time may remember something now or be freed of certain constraints and able to speak now. Salahuddin spoke in such a way that made us think he was educated by Scottish people. He was also very much of the scene at that time.

"We have tried to eliminate all possibilities of what could have happened to her. We have no real clues so we try to follow all leads. It is part of the ongoing investigation over the past 25 years."

Miss Macdonald, a history student at Aberdeen University, left her family home on Skye to travel to India with her friend Liz Merry. They were visiting the village of Sonamarg when Miss Merry set off on a two-day trip to see the Kolahoi glacier, while Miss Macdonald chose to stay behind.

On August 17, 1981, she went for a walk and bought some apples from a nearby trader. She was never seen again although her clothes and rucksack had been left in the guesthouse.

Six days later, her parents received the news, through a telegram sent from Miss Merry to her own parents, that Miss Macdonald was "lost in hills".

The Macdonald family, including Alison's brothers Sam, 43, and Derek, 38, have made several trips to the region in a bid to find information.

Yesterday, Kuldeep Khoda, additional director general of Jammu and Kashmir Police, confirmed that the case had been reopened.

He said: "Alison's father had been persisting with his own inquiry and he produced this CD of an interview with Salahuddin. He said his pronunciation and dialect were typical of the area where he lives and that he used certain words that the girl used to use.

"They have asked us to look into this and we have now asked our field agencies to reopen the case. The problem is that Salahuddin is in Pakistan. Salahuddin has never spoken about the case, but the father says he could only have got these words from his daughter and that he may have kidnapped and held the girl."

Mr Macdonald, who now lives in Invergordon, said he believed his daughter may have been kidnapped and later sold as a teacher.

He said the family would never give up hope. "When something is lost you keep looking for it," he said.

"You never give up.

"We are very much convinced that Alison is alive somewhere."