It’s easy to forget that Fiona MacKeown is a grieving mother: since her 15-year-old daughter Scarlett was found dead on a Goan beach last month she has been as much on trial as the men who drugged, raped and murdered the girl.

MacKeown’s hippie lifestyle and her decision to leave Scarlett in Goa while the rest of the family – a boyfriend and a brood of children who live on benefits – toured the beaches of southern India, has resulted in her being accused of selfishness and fatal neglect. Her image was damaged further last week when it was revealed that as a teenager she had served a year in jail for the attempted manslaughter of a man who tried to sexually assault her friend.

For the most part MacKeown’s grief has been hidden behind her feisty and successful campaign to force Goa’s notoriously corrupt police to treat her daughter’s death as murder. But tucked up on a sofa in her lawyer’s apartment last week, she finally crumples and sobs as she defends her parenting and lifestyle and describes the moment she realised her daughter had been killed.

MacKeown, 43, and her boyfriend Rob Clarke, 47, had travelled to India with seven of her nine children as a respite from the British winter. Home in Britain is a couple of caravans in a field in north Devon where they grow a few vegetables and have no mains electricity or water.

It is hard to classify MacKeown. Her children’s names – including Merlin, Kisangel, Isis Celeste and Trinity Willow – suggest mellow hippiedom. But she defines herself as a gypsy; when she sought planning permission to put caravans on her land she was backed by the Romany council. She is unconventional but when she says she was naive rather than negligent, I believe her. Those who have seen her with her children were struck by how bright, well mannered and affectionate they are.

With her brood of children, MacKeown would receive about £25,000 a year in benefits. In order to pay for the Goan holiday she told me she had saved £200 a week for months by living frugally – buying only rice to supplement the family’s home-grown vegetables and buying clothes for the children only from charity shops. Eventually they had about £7,000 for the trip, topped up by selling a pony for £1,000. It was a tiny budget for a six-month holiday once the flights for nine had been paid for.

They headed for the resort of Anjuna, which struck her as a peaceful, safe place. “It had a hippie vibe,” she says. It was more tolerant than England, where her children had been abused as “pikeys”, and MacKeown and her boyfriend were considering spending every winter here.

Their money ran out in January when they spent their last rupees on an old jeep, some hammocks and a barbecue set for a road trip south along the coast to Kerala. Scarlett was having the time of her life in Anjuna, taking free jet-ski rides and helping Julio Lobo, a 25-year-old tour operator, to organise dolphin trips.

MacKeown agreed that she could stay with Lobo and his aunt in their old Portuguese villa inland at Siolim, provided she joined the family every three days. MacKeown visited the villa and had dinner with the aunt and came away satisfied that her daughter would be safe. “Julio was a 25-year-old caring man,” she says.

When to allow a teenager new freedoms is a dilemma all parents have to face. But MacKeown also had blind faith in the goodness of strangers. She left Scarlett in the care of an elderly woman she had met only once, with no money of her own and without a mobile phone.

MacKeown and her family slept on a different beach every night, some of the children in the jeep, covered by mosquito nets, and the rest in hammocks. Scarlett came to visit by bus. MacKeown says her biggest regret is allowing her to return to Anjuna. They argued about how little time she was spending with her brothers and sisters and her determination to have more freedom. Like any 15-year-old she was pushing the boundaries, wanting more control over her life.

According to MacKeown, Scarlett had been in a sexual relationship, had smoked cannabis and sometimes drank beer or Bacardi Breezers, but was not out of control. She opens a photograph of Scarlett from a laptop and her daughter’s pretty face stares out, bright eyed and clear skinned. “It’s not the face of someone who’s on drugs. I’d know,” she says.

She would know. Her eldest son, Hal, had a serious drug habit that caused mental problems. MacKeown says she stopped smoking hashish when she realised how drugs had affected him. “I had to show a better example to my kids,” she says.

On February 15 MacKeown received a call to say that Hal had been seriously injured in a car accident in Britain. By then she was down to her last 1,000 rupees (£12.50), and her card was being rejected by cashpoint machines. Three days later, worse news came through. Lobo sent a text message to say Scarlett was dead.

When MacKeown got back to Goa, she discovered from her daughter’s diary that she had been having sex with Lobo and that in a row he had accused her of using him for “sex and money”. MacKeown believes Lobo’s aunt asked Scarlett to leave after discovering they were having sex and that she moved into a guesthouse.

The police told MacKeown that Scarlett had drowned while swimming fully clothed in the sea and she initially accepted that theory: “Then I went to see the people who found her and they said she was not in the water, but on the sand, and she was naked. They suspected she had been raped and murdered. She was warm when they found her. I walked between the shacks and found her underwear and shoes. Then I knew she had been raped and murdered.”

Forced into a proper inquiry, police last week released the findings. It now appears that at 4am on February 18, Scarlett walked into Lui’s Bar, a bamboo and reed shack on Anjuna’s low-rent seafront. Drunk and penniless, she hoped for a lift back to her room.

Police say she was quickly targeted by Samson D’Souza, a local man who last week allegedly confessed to her murder. D’Souza and an alleged local drug dealer, Placido Carvalho, took her into the shack’s kitchen where they gave her two ecstasy tablets, LSD and cocaine, police claim.

As the last guests drifted away, D’Souza took Scarlett to the back of the shack and raped her, police say. Later, after 5am, he took her onto the beach where he continued a brutal rape that left her with 50 cuts, bruises and internal injuries, until he noticed she was losing consciousness.

Police say D’Souza splashed her face with seawater to revive her but panicked when he saw someone passing with a flashlight. They say he dumped Scarlett in the sea and left her for dead.

Faced with this devastating account of her daughter’s last hours, MacKeown admits: “I didn’t understand the culture or the mindset of the Goan boys, right up to when she was killed.”

In her parallel hippie universe, she had done nothing worse than trust people. Her pierced lip quivers and she begins to cry for the daughter she will never see again.

“I don’t know what I will do. It’s changed my relationship with my children and made me want to spend every minute with them,” she says. “I want to go home as soon as I can but I want to feel that there’s justice for my daughter.”

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads