A family in Thailand have said they believe a woman who is thought to have been murdered and dumped in the Yorkshire Dales could be their missing relative.

The body of a woman was discovered by a group of walkers on Pen-y-Ghent in September 2004. While police initially suspected she had died of natural causes, a cold case team announced last year that they believed the woman may have been a “Thai bride” and that she was murdered.

A press conference in north-east Thailand on Thursday, reported by the BBC, heard a family had come forward about a missing relative who married a British man in 1991 and moved to north-west England four years later.

An efit of the woman. Photograph: North Yorkshire police

The woman’s mother has not heard from her daughter since 2004. The details of the missing woman, including her name and that of her husband, have been passed to North Yorkshire police. The force confirmed its cold case review unit had received a possible identity for the body.

The woman has become known locally as the “lady of the hills”. She was between 25 and 35 years old, of south-east Asian origin, about 4ft 11 tall, with shoulder length, dark brown hair.

When she was found she was half dressed, wearing only Marks & Spencer jeans and socks, with a bra hanging off her left arm. A postmortem suggested she had been dead for between one and three weeks.

The body was found by Peter Goodhew and a group of five friends. As they started to descend Pen-y-Ghent, conditions worsened. “It was really blustery, about 70mph winds, and we decided to abandon the walk,” he said.

When the six men passed Sell Gill Holes, a network of caves, they spotted something as they stopped to take pictures. “I glanced to my left and saw what I thought was a mannequin,” Goodhew said. “Logically, I didn’t think it could be a body.”

He approached the figure in the stream and stopped 10ft away. “I’d seen dead people before during my time in the navy. I knew that was what it was. The fingernails were missing and the body was bloated and swollen,” Goodhew said.

The group later noticed the woman’s form could be seen wrapped around rocks in the background of their photographs.

DCI Adam Harland, who is leading the investigation, explained last year the current line of inquiry was that the woman was a “Thai bride” and had been murdered by her partner.

“There are two major factors [that make this a likely murder],” he said. “She hasn’t been reported missing to the police, and that in itself is significant. The other is that she’s been moved away from wherever she’s died.

“As soon as you’ve got a dead body in your house, you’ve got to explain why it’s there. So when a body is moved it’s usually indicative of the fact that the person who killed them had a close relationship with them.”

An initial theory was that the woman could have died of hypothermia (up to 50% of hypothermia-induced deaths on land include “paradoxical undressing”). But this was discounted as temperatures in the weeks running up to the discovery of her body were too mild. She was also found without shoes, and none were ever uncovered, making it unlikely she was out walking.

The site where the body was discovered by a group of walkers in 2004. Photograph: North Yorkshire police

The exact cause of death has never been established as her soft tissue had started to disintegrate when she was found, though it was clear she had not been stabbed, beaten with an object or shot. Suffocation is a statistically common way for women to be killed by their partners, said Harland.

Many of the inferences about the woman have come from using stable isotope analysis, which allowed investigators to establish where she was when her bones, teeth and hair were growing. Tests of her femur show she was born somewhere tropical and oceanic, probably in an area east of India and south of China.

Her hair provided information on the two years leading up to her death. The strands contained isotopes peculiar to north Lancashire and south Cumbria, as well as two places in south Wales and three in mid-Scotland.

Harland said he believed the woman’s body was dumped on higher ground, which can be reached using a 4X4, and that the heavy rainfall washed her down the stream. The isotope evidence, combined with statistical data that suggests people tend to dump bodies between 50 and 80 miles from where victims are killed, has led detectives to suspect the woman was living in Lancashire or Cumbria when she died.

The woman was wearing a wedding ring made of Thai gold and had been taking birth control pills. “She’s been in a relationship here [the UK],” said Harland. “The relationship had probably failed and her partner told the people who knew them both that she had gone home.

“Perhaps their friends thought he was making a little bit of a fool of himself in the first place and weren’t surprised to discover that it had fallen apart, and therefore weren’t suspicious that she disappeared.”

Harland has urged people not to pay too much attention to the efit North Yorkshire police released. “The picture that was made was taken from the remains of the woman,” he said.

“When we find out who she is, we would like to speak to the person who was her partner in the last few weeks of her life. And we will ask him why he hasn’t noticed she’s not there and why he hasn’t told anybody else about it,” said Harland. “And I bet he’s going to have had access to a 4X4 vehicle.”