Linda Norgrove's parents are paying tribute to their daughter's life by continuing her work

Inside, there is a feeling of stillness, peace. A fire crackles in the grate, an open book is spread across the arm of a chair, but the focus of the room is the photograph on the mantelpiece above the fire. It is of the Norgroves' daughter Linda, her smile luminous, the effect boosted by the garland of trailing red lights wrapped around the picture, each light wrapped in a delicate skirt of red gauze. Hanging beside the lights and the picture are two origami paper cranes, brought by a Japanese friend of Linda's who came to her funeral. A traditional symbol of peace.

Linda Norgrove was a regional director of DAI, an international aid organisation, when she and three Afghan colleagues were abducted in Kunar, Afghanistan, on 26 September last year. Her colleagues were released but Linda was kept hostage and taken to a remote cattle farm in the mountains. On 8 October, a rescue mission was launched by special forces of the American military. Linda died in the attempt. At first, it was thought she had been killed by one of her captors detonating a suicide vest, but it soon emerged that she had actually been killed by an American grenade, thrown after one of the soldiers panicked. In fact, by the time it was thrown, Linda was the only one in the camp left alive. Disaster was snatched from the jaws of victory.

There is something special about the Norgroves. Losing a child, even one who has reached 36, is always one of life's most painful experiences. Sometimes, pain makes you noisy. Hitting out, shouting out, anything to divert you from facing your loss. But the Norgroves are not angry people. They don't rage or blame. Instead, they have set up a charitable foundation in Linda's name, to continue her work. And somehow, in their stillness, is the magnitude of their loss.

"We just feel sad," says Lorna. "These guys were in there dealing with that situation. We can't say, 'Why did he throw that grenade?' He might have felt his life was at risk." There is tendency in the modern world, when things go wrong, to call for heads to roll. Not here. "They made a mistake," says John. "Yes, they made a mistake," agrees Lorna. Full stop.

Before the rescue attempt was made, elders and leaders from the local village tried to negotiate Linda's release. They claimed to be close to success. But the military feared Linda was to be taken across the border to Pakistan and given to the Taleban for a ransom. The Norgroves were neither informed in advance about the rescue, nor consulted about its wisdom. But they are glad they weren't. To make an informed decisi

on, you need facts they simply didn't have. They had only anodyne snippets of information, filtered through military intelligence and the Foreign Office. "Imagine we had said, 'Yes, go ahead and do that,' how would we feel now?" asks John.

After the failed rescue attempt, Prime Minister David Cameron was quoted saying he would go over it a hundred times in his head, but he was convinced it was the right decision. There is a pregnant silence in the room. Are they convinced? "How can we possibly say yes?" asks John finally. "We can't answer that," says Lorna quietly.

The Americans ask families before they attempt a rescue, the British don't. "It's a really difficult one but I probably favour the British system," says John. But not in everything. "The Americans have a lot to teach us about treating people in the situation we were in, giving them information. I think the British system can be quite paternalistic." He turns to Lorna. "The inquest was quite paternalistic, wasn't it? Whereas the military inquiry conducted by the Americans ... I was just so impressed by that. They went into the detail. They gave it to you on the nose, gave you the facts. They were so totally honest and frank. I thought that was really, really good. We haven't had that honesty and frankness from the British authorities."

Linda wasn't a big fan of the US military. She thought they were too cavalier towards local people. But John was appalled when he saw an aid worker on television saying the last thing she'd want would be the Americans trying to rescue her. It would be a death sentence. "Linda would never have come out with that kind of thing." She was always respectful in her approach. She wasn't a Muslim (though a leaflet drop in the area she was abducted from claimed she was converting to help secure her release) but she observed Ramadan, fasting from dawn to sunset, not just when she was with local people but when she was alone.

She wasn't religious, and her funeral was humanist, but she kept a copy of the Koran and loved other cultures, other peoples. She taught herself Dari, the dialect of Farsi spoken in Afghanistan. Quiet, not extrovert, she would still end up chatting to the person next to her on foreign buses. Linda said it rained too much on Lewis to live there. It was too cold. If she'd been home on a wild day like today, she would have piled all her warm clothes on. But when they cleared her Afghan office out, there was nothing on the walls but pictures of home, images of Lewis and its magnificent beaches.

In the croft's sitting room, there is a scrapbook of little notes and reminiscences, some in halting English, from Linda's Afghan colleagues. DAI concentrates on employing local people in their projects, trying to improve lives in vulnerable areas. Reading the scrapbook, you see Linda through other people's eyes. It gives such a strong sense of her that she becomes less of a stranger. "Always she wanted to visit the needy and share her nice feelings with the community," says one colleague, Zarghuma. "I never heard an unpleasant word from her mouth. We will never forget her kindness," says another, Masood, who recalls Linda's instruction to stop off at her house before starting work at 7am. "She said you must have cup of tea because you come here so early. May Allah rest her soul in peace." The tributes pour on to the pages. "An extraordinary human being," writes one. "In life we loved her dearly. In death we do the same." Then there is Nasir, who writes: "I myself always think I lost my only sister."

As a child, Linda was reserved. She helped with the animals on the croft and shared a horse with her sister, Sofie, but it was Linda who took most interest, grooming, riding, training it in circles down on the beach. Later, she would gain a first class honours degree in tropical environmental science, a distinction in her Masters in rural resources and environmental policy, and study for a PhD, yet she wasn't particularly academic as a child. When she realised the limited work options on Lewis, she suddenly buckled down.

Her love of travel began in childhood. The family kept cattle and every two years they sold off their calves to buy tickets for faraway places. Since they lived on a small island, the Norgroves thought it good for their daughters to see other cultures. Linda was sick all over the terminal building in Thailand after a long flight, but though she never liked flying much, she was keen on adventure. The family went trekking in the Golden Triangle, the opium fields on the border of Burma and Thailand.

Linda was homesick when she left for her first job in a hotel on Skye but after that she spent six months working in a stables in Belgium and in subsequent years became remarkably independent. Her second year at university was spent on exchange in America and that influenced her greatly. "She passed courses in sub-aqua diving and drumming – you could actually get credits to your degree from doing these things – and that was so unstuffy compared to Aberdeen," says John. "I think the very positive attitude the Americans have was important to her and changed her attitude quite a bit."

She even went cycling solo across China, though she was later joined by a friend. "She found China quite difficult," says Lorna. She was 5 ft 6 and a lot taller than most Chinese, especially women, and she had a lot of blonde curly hair – and big feet. "Everywhere she went, she was surrounded by people pointing at her feet and laughing."

Although her interests originally were zoology and ecology, an important change in her thinking developed. When she worked for the World Wildlife Fund in Peru, the tremendous poverty there made her focus more on people. She put forward a proposal at a WWF conference that indigenous people must be considered first in endangered environments – a proposal that changed WWF policy.

In Afghanistan, she loved both the people and the landscape. She had worked for the UN there for three years but in 2008 went to Vientienne in Laos. The job didn't suit her. Linda liked being out in the field, going into the jungle or the mountains, going through villages and meeting local people, but Laos was office based. When she was offered a job back in Afghanistan with DAI, managing an extensive project with a budget of millions of dollars, she knew this was her chance to make a difference.

"I didn't want her to go back," admits Lorna. "The first time she went, I tried to dissuade her," says John. "But she was determined. The second time, she was 36 and had been abroad since she was about 22 and seemed quite good at gauging risks. She was quite sharp, on the ball, and hadn't come to any harm."

True, she'd had a few near misses. A hotel where she went to the gym was attacked on the night she regularly went but, for once, she wasn't there. She was going home the next day and had work to finish. She'd also had her bag snatched in various places around the world. But she retained a belief in human nature – though not a nave one – and particularly liked the Afghans who are so renowned for protecting guests. ("Do not call the kidnappers Afghan," wrote one of Linda's colleagues in the memories book, "all the world knows ... Afghan people are famous for their hospitality.")

"Linda always said that she felt very safe when she was in the village," says Lorna, "because when she was in somebody's house, they would protect her with their life. She always felt that."

After the abduction, the kidnappers were said to have asked: "Where is the big man?" It is taboo to abduct women in Afghanistan and it is thought they really wanted Linda's boss. "I still think we are dealing more with criminals than the Taleban, as such," says John. "It's a bit like the IRA in Northern Ireland where the political side is used as an excuse for criminality. People in this particular valley had been known for their criminality over a period of time."

The day they heard Linda had been kidnapped, they were out climbing a local mountain. It was beautiful day and as they walked back through the village, a neighbour told them the police from Stornoway were looking for them. Initially, they were optimistic about Linda's chances. And perhaps things would have turned out well if the rescue hadn't had to be mounted at night by helicopter. There was no other access and since successful rescues tend to happen fast to disorientate the kidnappers, flying helicopters in during the day gave too much warning. There was also a serious risk of them being shot down.

The American Chinooks arrived in darkness in the early hours of the morning, coming under fire immediately in the remote mountain settlement the kidnappers had forced themselves on to. Several kidnappers were shot dead in the exchanges, but one had dragged Linda outside to some steps. Later, in an infrared video, her figure would be seen but the rescuers thought she was inside the building. One of the soldiers' rifles jammed and it was he who threw the grenade. It wasn't only the kidnappers who got panicked and disorientated in the darkness.

John forced himself to watch the Americans' video, a difficult task. Lorna didn't but it was the right decision for her. "I couldn't," she says. The video reassured John that what they had been told added up. What is "truth" anyway? he muses. Truth changes, depending where you are looking from. The Norgroves feel they are as close to it as they can get. Blame won't bring Linda back. "If the grenade hadn't been thrown, it would have been a total success and we would have been dealing with a totally different situation," says John.

Lorna has put tea and home-made bread on the table, and cheeses from a local delicatessen. This is a very hospitable house. We are going to the beach for photographs, despite the weather. Lorna looks at my thin jacket and unsuitable shoes and hands me a fleece, waterproof and boots. But first, she hands round the bread. It's so uniform, it looks machine cut – how did she manage that? "Thank you, Catherine," she says, with just enough suppressed irony to suggest this has been the subject of some teasing. John is laughing. He approaches bread cutting with military precision. Lorna is more organic. Well, isn't that just men and women neatly summed up? Military precision one side, organic growth the other.

John protests at that – says it's obvious which I'm favouring. But there's an undercurrent of humour, of fun.

Linda had a sense of mischief too. At her funeral, school friends confessed pranks, like the time she set off the hostel fire extinguisher. "She was game for adventure. She wasn't timid," says Lorna, "but she was careful." There have been suggestions she took risks but it wasn't any more true for her than anyone else. Life is a risk. The Norgroves skyped Linda once a week and saw her twice a year. Sometimes she would come home, and sometimes they would fly out to meet her. They went to Ethiopia once. In a small bar, locals turned up with a violin and some songs to entertain them in the hope of a few dollars. Their hotel was close by but walking back, Linda suddenly said: "We shouldn't be doing this. It's too dangerous." "She clocked it much quicker than I did," says John. "She didn't take silly risks at all."

Down on the beach, the sun briefly appears. Sheltering by the rocks as a nuclear mushroom cloud of spray explodes out at sea, I watch the Norgroves walk along the beach, hand in hand, as they wait for the photographer to set up. There is something very unified about them, very dignified. John has that reassuring dependability; Lorna has a simultaneous, almost contradictory, strength and vulnerability. She finds it helpful to go running each morning.

"I find it very therapeutic. If I was stuck in the house all day, I would find that very hard. But as to how I cope with the grief ..." There is no choice in life is there? "Exactly," she says, with some animation. "You just have to get on with it." She sees as much as she can of her daughter Sofie and two grandchildren. But it changes your life forever, she says.

When asked the biggest change in him, John says quietly: "Less smug, I think."

They both paint and have made their pictures into postcards. There is a beautiful painting of Lorna's in the sitting room, an intense, vivid green and yellow landscape. It's full of joie de vivre, an extrovert vision from a quiet woman. But Lorna hasn't painted since Linda died. "I haven't been able to," she says. She no longer goes to class and finds being in groups of people quite difficult. But there is something about Lorna; you suspect when she does pick up a paintbrush again, the creative emotion could flood out of her.

An art auction will be held on 9 April at the Morven gallery, Barvas, to raise funds for the Linda Norgrove Foundation. Local artists have contributed work and 30 pieces will go up for auction, including internet bids. It is the foundation that has given the Norgroves' grief a focus in recent months. One of the first things they did was attempt to help the families of innocent local farmers who were killed in the rescue attempt.

John, a retired water board engineer, still does consultancy and the couple are overloaded with foundation work. They know they cannot run it alone. They hope to have an annual income of around 100,000 and have a number of fund-raising marathons planned. They are currently looking at helping a widows' home in Jalalabad. They want to help the powerless in Afghanistan, which generally means women and children, an aim Linda would have approved of. In the memory book, a colleague called Fanzia has written: "Linda was very kind to all staff, especially women, because she knew that we needed more kindness."

It is impossible to hear Linda described by the parents who loved her without wishing to have met her. It wouldn't seem right not to stop at the graveyard on the hillside on the way back to the airport. But I cannot find the grave, and the sleet is driving almost horizontally in the bitter wind. Eventually, I run back to the car, catching a glimpse of beach in the distance, imagining a girl riding her horse in circles on sands somewhere on this island. She packed her life, Lorna had said, and that was a comfort. She made a difference. Perhaps it is not how long your life is that is most important, but whether you lived a life that mattered. n

For information and to make a donation visit www.lindanorgrovefoundation.org and www.morvengallery.com

• This article was first published in the Scotland on Sunday on March 27, 2011