THE DAY WILL COME WHEN WE'LL KNOW HOW OUR EMMA DIED' The murder of Emma Caldwell was the last act in a life already torn apart by grief, drugs and prostitution. But a year on, her family still don't know how or why she was killed. Michael T

There she is, points out Margaret. Her baby. Her girl. Emma Jane. Margaret stops and picks at the sleeve of her jumper. When Emma was murdered she was the kind of girl who couldn't see other people's bad points. She couldn't see she was being manipulated. Emma was 5ft 6ins tall, slim, with shoulderlength hair, a heart-shaped tattoo on her back and grey-blue eyes. She loved listening to Candi Staton, Brandy, Anastacia and, when the mood took her, the classical tenor voice of Andrea Bocelli. One of her favourite poems was This Life That I Have by Leo Marks.

In one picture Emma is wearing a green raincoat, nuzzling up to her horse. "It was horses from a very young age, " says Willie, softly. "When Emma was young, if you asked her what she wanted, meaning a can of juice or a packet of crisps, she'd always say, 'A horse.'" Margaret attempts to smile, but cannot. Instead there is a flood of tears.

According to Strathclyde Police, Emma was last seen on April 4, 2005, near a women's hostel in the Govanhill area of Glasgow at around 11pm. She had been working as a prostitute to fund a drug habit. Emma was reported missing on April 11, 2005, but her badly decomposed body was not discovered until May 9, in a remote woodland spot between Roberton and Rigside, near the South Lanarkshire town of Biggar, by a dog walker. The condition of her body was such that the police have still not been able to ascertain exactly when Emma was killed. She was the eighth Glasgow prostitute to have been murdered in the past 14 years, although police have always insisted their deaths are not linked. Only one conviction has been secured in that time.

The area around Roberton is beautiful, with tidy homes, farms and spectacular scenery. Thirty miles from Glasgow, close to main routes such as the M74 between Glasgow and Carlisle and the A702, the area is one of the finest you pass through on any trip to southwest Scotland. The idea that such a horrendous crime was committed here - or at least of a body being dumped here - is at odds with the nature of the place. Birds sing all around. The earth smells sour and damp. You can even hear insects moving. It's an area popular with cyclists, walkers and birdwatchers. Here, you can simply disappear into the trees.

The police believe they have traced everyone they think has, or had, legitimate access to the area, from people who work and live on the 'farms to school bus drivers, mechanics and delivery people. They've also spoken with people who laid pipes, to gamekeepers and even hang-gliding enthusiasts. The question remains, however, of why the case is proving so difficult to solve.

According to the officer in charge, Detective Superintendent Willie Johnston, Caldwell's lifestyle created major problems. "Ninety-five per cent of the girls who are prostitutes are class A drug users, " says Johnston, a voluble, forthright 48-year-old with almost 30 years' experience in the police. "There will be large numbers of people involved in that business [drugs and prostitution]. The other aspect of Emma's lifestyle was that, although she did have regular clients that would use her services, she would still go with strangers. Some are violent, others are extremely violent. Others are men who have a family life completely separate from the activities of Emma Caldwell or other girls of a like mind."

According to the police, there are thousands of prostitutes in the red light area of Glasgow; "a whole subculture of activity, " says Johnston, "that swirls around in that pool." While most of her regular clients have already been ruled out, the police can't rule out some kind of encounter with a stranger. There is also the possibility of a chance encounter, or that she had fallen out with another prostitute.

In April this year, police released CCTV footage of a car they hope will hold the key to the inquiry. The grainy pictures capture a woman getting into a silver Skoda Felicia next to a casino in the Broomielaw area of Glasgow. The footage was from the night Emma disappeared. Police have interviewed and examined every owner and driver of vehicles of that particular type in Scotland; they've also carried out vehicle owner and driver enquiries in England. In the footage, Emma was wearing a dark-brown suede jacket with an imitation fur collar and cuffs. The dark jacket is still missing, as is her dark coloured handbag.

But while the police insist the CCTV footage at the hostel and next to the casino are perhaps the last sightings of Emma, another potential sighting has emerged. A woman, who does not wish to be named, insists she saw and spoke with Emma on a Glasgow subway train four days after she was seen leaving the Inglefield hostel in Govanhill.

The woman, who twice contacted the police on one of their hotline numbers, gave details, but her calls were not followed up. On the day she believes she saw Emma, she was visiting a friend in Cardonald, south-west Glasgow. And she still has a note in her diary of the day she made the trip. It was April 8. "I'm absolutely certain it was her, " she says.

The woman boarded the subway at Buchanan Street station, carrying a box of flowers. It was around 12.30pm. She was going to Shields Road underground station to pick up her car. "The girl got on at St Enoch's underground, " she says. "She sat across from me. There were two men, kind of business-dressed and, I think, one was reading a newspaper. I kind of noticed the girl, rightly or wrongly. I just thought, drugs or alcohol. I thought she looked a poor soul. You know how you do that? Sum someone up in a few seconds? It's terrible, but you do. You quickly gauge people.

"Her hair was quite long and she was very pale. She was wearing a kind of heavy coat. I think there was something like a hood at the back, quite big. She had a very thin face and quite red eyes. She had something in her hand. I can't remember what it was, but she was kind of looking at something. She was quite slumped. At one point she looked across and that was when she said to me, 'These are beautiful flowers.' I said they were lovely. I said, 'I'm going to visit my friend. I'm taking her this box of flowers.' She said, 'That's a really nice thing to do.' She was quite polite. And maybe I didn't associate the accent with what she looked like.

"She said, 'She'll appreciate that. That's a really nice thing to do. It's a nice thing when somebody does that for you.' I said my friend would appreciate it. She said, 'That's nice.

That's good.' I looked over and the man reading the newspaper looked over the top and smiled. I got up at Shields Road. When I got out and was walking along to go up the stairs the train passed and she turned round and waved, she wriggled her fingers to wave. I went to get my car and that was it."

The woman believes her first call to the police was roughly two weeks after her alleged sighting - following a newspaper photograph and report of Emma's disappearance. The second call was about a month later.

"When I opened it [the paper] I looked at the picture - it was quite a big picture - and I thought, 'That was that girl, '" she says. "I was on my own sitting here [in the house she shares with her partner]. I found myself saying out loud, 'There's that girl. That girl I spoke to.' I said it like that. I didn't say, 'I know that girl, ' or 'She's familiar.' I said, 'That's the girl I met on the underground.' It [the paper] had a number. Because I was on my own I picked up the phone and called my friend. I told her what had happened. I said, 'There's a picture of this girl and I spoke to her.' They [the paper] asked to phone." Her friend told her to phone the police.

"I put the phone down [and] phoned [the police]. I said I was absolutely certain it [the picture] was the girl I saw on the underground. I told them what I'm telling you. But I didn't hear any more about it. About a month later I mentioned it to friends again and one said I should call the police again. I did, I phoned again. I'd taken a note of the number. I never heard any more. I can't say that any time since then when I saw her picture I changed my mind. I'm very sure it was her." She is still willing to speak with the police.

The Holmes Unit incident room, the engine room that drives and maintains the administration in cases of murder and major incidents, has, since last May, dealt with more than 2,700 statements and has around 8,600 names on file for various reasons relating to the case. But nobody called back this potentially crucial witness. If this was Emma on the subway - and the chances of proving that it was are now remote - she would be likely to have got off at Kinning Park, Cessnock, Ibrox, Govan or Partick: the stops after Shields Road. If not, she would probably have travelled in the opposite direction to arrive at her destination by the quickest route. If it was Emma, anyone else who may have spotted her after April 4 might have been inclined to dismiss their sighting, given the reports that she was last seen at the hostel.

In March this year, a community centre in Bridge Street - one subway stop from St Enoch's underground entrance - was sealed off and searched by police hunting Emma's killer. It is believed a car was removed for forensic examination and several people questioned. The three-storey community centre is popular with Glasgow's Turkish community, particularly private taxi drivers who often park outside it at night. A Turkish immigrant is believed to be "of interest" to police investigations, according to one officer I spoke with.

Emma Caldwell hid her secret life from her parents. They did not know until after she disappeared that she was a prostitute and they still don't know exactly when this phase of her life began. What they did know was that she was on heroin, having turned to drugs following the death in 1998 of her older sister, Karen, from non-Hodgkin's lymphoma. The day I arrive at the Caldwells' house is the anniversary of Karen's death. Emma was 20 when her sister died aged just 31. Margaret and Willie also have a son, Jamie, 29, who lives nearby with his partner. He was to be married this spring, but the couple have put that on hold until the family can bring Emma home. The Caldwells haven't been allowed to bury her body because it may be needed as evidence. "Then we will all be able to say our goodbyes, " says Margaret.

Karen and her husband had already lost their first boy, Kenneth, to illness. "Both of our grandsons were born without an immune system, " says Willie. "Kenneth died in NewcastleGeneral Hospital. He'd been given a bone marrow transplant. It was unsuccessful. He was one and a half. Stewart, who stays with us now, was one of the first successfully treated in the so-called 'bubble unit'. He's 12 now." The patients there - dubbed "bubble babies" - are all born without an immune system and are unable to fight off infections like most children. Each child needs to be treated with a bubble of clean air, known as sterile isolation.

"When Karen eventually died it left a huge hole in Emma's life, " says Margaret. "She never seemed to smile. There was nothing there." Willie adds: "Emma seemed to sort of lose the fun out of her life. That spark, although still there, had dulled." It was later reignited. By heroin.

When she talks about her daughters, the physical pain in Margaret's chest seems overwhelming. "Our girls are all around us, " she says. "We have them in our hearts. We called them our little ducklings." When Margaret's out and someone passes wearing Emma's favourite perfume, Jean Paul Gaultier, she gets a lump in her throat, her eyes sting with tears. "She seems so near."

Emma Jane Caldwell was born on January 31, 1979, at the Vale of Leven Hospital in Alexandria, Dunbartonshire. It snowed heavily that night. The plan was for Margaret's parents to look after the other children when labour started so that Willie could go to hospital, but the snow was so thick they couldn't make it. When the ambulance arrived, Margaret was carried through the snow to it. After a few miles the driver thought they might have to deliver the baby in the ambulance. Finally they reached the hospital. They called Emma "our little snowdrop".

"We were so proud, " says Margaret, "and we're still proud of her." From listening to her speak, it seems like a lifetime ago to her now when Karen, Emma and Jamie were children. "Both girls were always alert, " says Margaret, "frightened they might miss something. Jamie was a textbook baby, the kind you could have a dozen of and never break sweat. Despite the INVESTIGATION beginnings, Emma became an adorable child who chatted all day. She became a great companion for Jamie who, by nature, was much quieter. They never left each other for a moment. They were best friends."

The couple, who ran a pub in Cardross for ten years, had a big garden with plum, apple and pear trees. Near the bottom was an old Victorian greenhouse with wicker chairs and a table. "Jamie and Emma loved it and often played there on rainy days, " says Margaret. "When my mum and dad came they all had tea in the greenhouse. The table would be laid with a cover, then all the goodies would be brought from the house. We used to watch them from the window and think how lucky we were. Losing a child is like no other loss. A child being murdered must be the ultimate sacrifice for a human being."

About a year after Karen's death, Emma got a job as a stable girl at a riding school in Glasgow. She met a man there, an amateur jockey, who became her boyfriend. "He offered drugs as a way to escape her unhappiness, " says Margaret, bitterly. "Things weren't working out there. She came back home. About six months later we found out about the drugs." Unbeknown to them, the boyfriend had been bringing drugs to their house. When he stopped coming, Emma began having withdrawals. Although her family barely knew what heroin was, the revelation was followed by trips to the doctor and hospital. They were told nothing could be done and Emma got increasingly worse. They vowed never to buy her drugs, but one day she was so bad Willie gave her GBP10 to see her through the night.

In 2003 she got a place at the women's hostel in Glasgow and her parents helped her in the best way they could. If Willie visited he would bring her washing home and her mum would do it, returning with it when she visited Emma during the week, along with the ironing, fresh orange and deodorants. Margaret would buy her clothes and Willie topped up her mobile phone card every Wednesday. Her room at home was decorated and they even promised her a new horse. They bought a television for her room in the hostel. She called it "my friend in the corner", telling them that, no matter what, she'd "never give it away". She never did.

When Emma turned to prostitution is not known definitively. But one night, around six months before she was killed, she told her mum there were one or two working girls at the hostel. "I said to her that it was so sad, " says Margaret. "How are they going to be able to tell their children and their grandchildren what they did?" Willie cups Margaret's elbow. "I think she was sort of testing to see how we'd react. We just found it sad that people found themselves in this position." But Margaret diligently washed and pressed old sports clothes belonging to her grandson and Emma took them to the girls who had nothing.

While rumours and innuendo are always rife in this kind of case, according to one source Emma was paid to strip at a party about five years ago. She didn't know it at the time, but some of the men there had been schoolmates. "We knew her from school, " says the source. "The boys just thought it was a bit of a laugh. It's a terrible thing now, though." Nobody knows how long Emma was stripping for or if she had been working as a prostitute before then. But stripping is often a quick way to make money and the first steps to prostitution. And Emma needed money. She had a habit costing almost GBP100 each day.

As well as the raid on the community centre in Bridge Street and the seizure of an abandoned caravan in Golspie, Sutherland in July last year, the police still have a number of other areas of concern. Tracing the driver of a silver 3-Series BMW captured on CCTV doing a three-point turn just as Emma was walking along Inglefield Street. Identifying the owner of a dark-coloured Skoda Octavia, marked with a Glasgow private hire taxi plate and seen close to where the body was found. Finding the man whose DNA was discovered near to where Emma's body was dumped. A police check on the UK national database failed to find a match; neither did it match those men the police asked for voluntary samples.

In almost 30 years of murder investigations Detective Superintendent Johnston, who is due to retire later this year, has solved all his cases. "I never make it personal, " he says. "I'm a public servant, here to do a job. Come the day, come the hour, if we have not solved this case with all our leads and enquiries, then I would say that we have done everything, but I'm sorry we haven't caught the person responsible. However, we never put these cases away in a drawer." The look on his face tells a different story. Whether he admits it or not, solving Emma's murder is personal.

Margaret and Willie take me to the park in Renfrew where Emma and her mother used to go walking every Sunday. "When I go to bed, " says Margaret, "I just dream of her. 'When I come home, Mum, when I come home . . .' That's all she ever spoke about." They have visited the spot where her body was found three times. It does not get any easier. "You find yourself almost unable to breathe, " she adds. "Your heart pounds in your ears. You come upon the little clearing where your child was dumped, hidden, left to die, perhaps murdered. You can only sob and say her name and ask why this person took our beloved child's life. Perhaps in years to come we will be able to leave it behind, especially when we have a place at home for Emma."

Murder is never a normal death and so from the start there has been nothing the couple can relate to. Even the way Emma was killed is kept secret by the police, because this information will only be known to the killer or somebody spoken to by the killer. "The day will come when I will know [how she died], " says Willie, "and I content myself with that. As far as the person being caught, it's justice that I want, not revenge. I don't think revenge works. It would destroy you." Margaret looks at her husband. "At the very beginning there was this primordial thing, " she says, her voice aching with sadness, "where you just wanted to go out there and, well, if you could get him yourself . . ." Her voice trails off. "It's not something you can deal with.

"But even if the police arrest someone we'll never get back Emma. We will always be known as the parents of Emma Caldwell who was murdered." A track of black mascara runs from her eyes. The smell of Emma has gone from her daughter's clothes. There is no trace left in the fabrics. But her parents will always remember. "It sounds daft, but she was never rude. She never, ever answered back."

Willie smiles. "You'd tell her to come in when the street lights came on at ten to nine, " he says. "Jamiewould be there on time. Emma would be there five minutes later with two friends sitting outside. I can still see her sitting there now." He pauses. It doesn't really mean anything. It's just a memory. But memories are more dangerous than bullets.

Anyone with information relating to the murder of Emma Caldwell is asked to call the Incident Room at Cathcart Police Of. ce on 0141 532 4943 or Crimestoppers on 0800 555 111, where anonymity can be maintained.

DANGEROUS PROFESSION

In Glasgow over the past 14 years eight prostitutes have died in suspicious circumstances, including Emma Caldwell; to date only one conviction has been secured. In 1991, Diane McInally, 23, was found dead in Pollok Park. Two men were charged, but released due to lack of evidence. In 1993, the body of 26-yearold mother-of-two, Karen McGregor, was found near the Scottish Exhibition and Conference Centre. The jury returned a not proven verdict. Leona McGovern, 22, was found stabbed 17 times and throttled in a car park in 1995. A man charged with her killing was found not guilty. In 1995, Marjorie Roberts's body was found floating in the Clyde. Police couldn't say whether the 34-year-old had fallen in or was pushed. Jacqueline Gallagher, 26, disappeared from the city centre in 1996. Eight years later, a man was acquitted on a not proven verdict. In 1997, Tracey Wylde, 21, was found beaten to

death in her flat. Nobody has been convicted of her killing. In 1998, Margo Lafferty, 27, was murdered after picking up a client in Glasgow. Three years later Brian Donnelly, of Old Drumchapel, was jailed for life for her murder.