ON PRESTWICK beach, all is calm. The tide is high, leaving just a narrow strip of seaweed-strewn shore exposed, and the water barely ripples in the slight breeze. The dog-walkers, joggers and cyclists that dot the promenade are undeterred by the oppressively low clouds that signal imminent rain. But to Guje Borjesson they seem heavy with untold secrets.

It was on a day like this that her 30-year-old daughter, Annie, last walked along the seafront. That day was December 3, 2005. Annie, who left her home in Sweden to study English in Edinburgh, had fallen in love with Scotland. She was looking for work after a placement at the Whisky Heritage Centre on the Royal Mile. But it was here in Ayrshire - 80 miles from her adopted city - that she was found dead.

Two years on, Guje, and Annie's best friend Maria Jansson, have returned to the place she was last seen alive. Tomorrow they will hold a memorial service on the shore. But they are not here just to remember - they are still looking for answers regarding her death.

The beach seems a good place to start. We walk briskly, glancing out to sea. Guje points to a place on the shore where a witness claims he saw Annie talking to two men. It was just after 4pm, and beginning to grow dark. But it wasn't until 8.30am that her body was found by a local man walking his dog. We slow as we reach the spot, just short of the two abandoned cottages that sit back from the shore, where her body once lay. Now there is nothing there but a tumble of seaweed.

The police concluded that there was no foul play. The official outcome of their inquiry was a verdict of suicide, or possibly an accident. They also insist that the matter was thoroughly and properly investigated. But Annie's family contest the police's findings, claiming she was a victim of crime. They insist her case was never properly investigated.

Guje rejects outright the possibility of suicide. "I knew my daughter," she says. "She loved people, trusted people, she was very social. We had a good relationship and she was a communicator. If anything was wrong she talked it through."

Although Annie hadn't booked a flight, Guje believes she was on her way home and planning to buy a stand-by ticket. She was seen on Prestwick Airport's CCTV the day she died, had called Maria to say she would visit when she returned home, and made an appointment with her Swedish hairdresser for December 5. Her passport, along with books due to be returned to the library near her family home in the small town of Tibro, were found in her bag.

Before she left Edinburgh, she paid a month's rent on the flat she was staying in. And at her last visit to her local swimming pool that week she had bought a multiple swim pass. "That is not the behaviour of someone who would take their own life," says Maria.

As for an accident, Maria and Guje claim that is improbable. Annie was a strong swimmer whom they believe was unlikely to have accidentally drowned in water less than a metre deep at high tide.

Instead, they strongly suspect Annie was murdered. She was found without her jacket on. Why, they ask, would she have removed it on a cold December day? Guje also claims there were unexplained bruises on Annie's body, including one on the left temple consistent with a blow to the head. Annie's long blonde hair, which throughout her life she refused to cut, had been hacked away in clumps. Her Filofax, which she always carried, was missing from her bag and has never been found.

Guje believes her daughter seemed to be in some kind of jeopardy in the last week of her life. Annie called her brother at home from a phone box outside her flat to express her fear that someone might be trying to track her down over the internet. She asked him not to phone her back on her mobile or home phone as she was worried that someone would overhear. Guje is unclear whether her daughter meant the phone was being tapped, or that someone who was with Annie would be listening in.

"Who could hear? What was she worried about?" wonders Guje. "I called her on her mobile anyway on December 2 and I asked what was wrong. She told me that she couldn't talk about it, and that she was with a friend. But I told her we were worried. Then she said a strange thing: You have to respect this but I have to take care of this myself.' "I was taken aback," Guje continues. "So I thought, well, she is 30 years old so maybe I have to trust her." Guje resolved to give her daughter some space, and to call back soon. But before she could make the call, Annie was dead.

At 11.30pm on December 4, there was a knock at the door of the Borjesson family home. "I was lying in bed. My son came in and said that the police were at the door," says Guje. "I went to the hall and I knew something must have happened to Annie. They asked me to confirm that she was my daughter and said she had been found in the water. All around me my family started to scream and cry and I just stood there. It felt like I was freezing from the inside out."

In her head Guje replayed Annie's last telephone call and told the police officers that her daughter may have been murdered. They gave her a number to call and she sat up waiting for morning, so she could impart what she knew.

When she called, the Swedish police insisted it was a matter for the Scottish police and gave her another number to call. It turned out to be the number for a Scottish force, but not Strathclyde. It wasn't until that afternoon that Guje eventually got through to the right place.

"At last I got to speak to a policewoman and told her everything I knew about Annie, about what had been happening in the last few days; everything I could think of that might be relevant." But Guje says she slowly realised the policewoman on the other end was not asking any questions. "I presumed they must be gathering information and the questions will come later." They never came.

Instead, within days, the Scottish police broached the subject of suicide with Guje. She says she initially understood the police's line of thinking. Of course, not knowing Annie like she did, they could not be expected to share her conviction that her daughter would never have taken her own life.

Annie was, according to Guje, a bright, free-spirited individual. Born in the southern Swedish city of Malmo on February 7, 1975, she seems to have lived life to the full. "When the wind was blowing she would put her roller-skates on because that was when she could go faster," says Guje. "That was the way she lived her whole life. She was curious; she wanted to see and experience things."

On graduating from music college, Annie sang in a band, took various customer service jobs and had a diverse circle of friends. It was no surprise that she wanted to go to Scotland, says Maria, who remembers her friend would sing in the street, not caring who stared, just because she was happy. "She loved Scotland," recalls Maria. "I was planning to visit her, but you always think you have plenty of time." Guje had also been planning a visit.

The geographical distance made Annie's death all the harder to take. Since Annie's family had never been to Scotland, they couldn't visualise what had happened. It was two weeks before they saw the remains in a local funeral parlour. "The police had told me the body wasn't damaged," Guje claims, "but she was covered in bruises and her hair was hacked off in pieces." She phoned Maria, who, keen to help her find answers, repeatedly faxed and emailed the police their questions. The women say their questions went unanswered.

Alongside the body was a parcel containing the clothes Annie had been wearing when she was found - a red T-shirt, blue jeans and trainers - each in individual police bags, still damp and filled with sand. It seemed to the family that no-one had touched the contents of her bag, which were glued together with seawater. Nor, it seemed, had anyone opened the back of her phone to check the SIM card for contact numbers.

When the autopsy report arrived, it seemed incomplete. The family claim that several of Annie's bruises, including the one on her left temple, went unrecorded and that the toxicology reports were not included.

While Guje and Maria battled on for answers in Sweden, Guje's husband Karoly and son Charlie went to Scotland to see the spot where Annie was found for themselves. "The police picked them up at the airport," says Guje, but she claims that when the party reached the beach the police could not locate the correct site. "One pointed one way, and the other one in the other direction," she says. "By the time they had decided, my son and husband didn't know whether to believe them." It was later discovered that they had been off by around 50 metres.

Karoly and Charlie had more luck with finding CCTV footage of Annie at the airport. Guje claims that police had initially told her there was no sign of Annie in the footage. But within an hour of her husband and son making a face-to-face request for it to be rechecked, Annie was spotted. "The police called to tell me that and I said: Great - what happens now?' But they said it didn't change anything," says Guje. In May 2006, the procurator fiscal informed her that the case had been closed.

Guje asked for an autopsy to be carried out in Sweden. Although pathologists noted the bruisings and huge amount of water in Annie's lungs seemed strange, tests were inconclusive. While they waited for more results, Annie's body lay for more than a year in the funeral parlour's deep-freeze.

"It became untenable," she admits. "My husband would go and walk around the funeral parlour grieving." The funeral was held in June this year and offered some comfort. "Now we have a place to grieve," says Guje.

For Maria, it was hard. "As I looked into that big, deep dark hole in the ground I wanted to scream out: Don't put Annie in there'." She threw her bouquet, with a single thistle, into the grave and the skies opened. "It felt like the angels were crying."

Still searching for answers, both women claim subsequent talks with the Scottish authorities did not go well. "I was told the investigation was classified and that I could not get the documents released under the Freedom of Information Act because it was not in the public interest," says Guje. "I am a mother trying to understand the death of her daughter. It's in my interest. Is that not enough?" The apparent lack of compassion shook her.

Strathclyde Police insist, however, that a proper investigation of Annie's death was carried out. A spokesman for the force said: "The death of Annie Borjesson was thoroughly investigated by Strathclyde Police. The procurator fiscal and the Crown Office were completely satisfied that there were no suspicious circumstances. Miss Borjesson's mother has sat down with both the procurator fiscal and the Crown Office and had all of this explained to her."

But Guje remains unsatisfied. Now, with Maria's support, she is upping her campaign for a Fatal Accident Inquiry, usually only granted where there are issues of public safety or matters of general public concern arising from a death. She also has written to the Lord Advocate, Elish Angiolini, requesting a response. If necessary, Guje says she will fight for a change in the law.

Support is growing from other families who either have been victims of injustice, or claim to be such. They include policewoman Shirley McKie's father, Iain. Money raised at the memorial service will go to the Miscarriage of Justice Organisation (Mojo).

While in Scotland, Guje and Maria hope to track down new witnesses and talk to Annie's friends in Edinburgh who, as they have never been interviewed, may help shed light on what happened.

Since Annie's death, Guje has not returned to her job as a museum historian. "What would I do there now? Talk about the death of my daughter?" She says she is often distracted. Sometimes in the supermarket she wheels away the wrong trolley and doesn't know how to explain her behaviour. "I feel like I'm going crazy," she says. "Sometimes it just gets too much but I can't give up. If I just pull the covers over my head nothing will be done."

Even dealing with a normal death' is hard, says Stewart Wilson, director of Cruse Bereavement Care Scotland. "If there are lingering suspicions about how that person died, and whether it has been adequately investigated, that must be torture."

John McManus, Scottish secretary of Mojo, is also frustrated. He claims that such investigations are, in general, not sufficiently open or accountable in Scotland. "If you hold back evidence, no matter how inconsequential, it makes people wonder what else they aren't being told," he explains. "People end up feeling helpless."

Tomorrow's memorial service will start with a "silent walk for justice", highlighting the struggle of families who believe the deaths of their loved ones were inadequately investigated, or those Scots who claim they were wrongfully imprisoned or otherwise let down by the judicial process.

"If we achieve what we are struggling to do I will feel like we have at least made something good out of this," says Guje. "Annie always wanted to help people. I know that she would have wanted us to do the best out of her death."

Gazing out to sea, she adds: "But I really just wish that she was still alive."

For more information, or to contact the family, go to www.annierockstar.com