The words come out quietly, but the distress is clear. ‘I never taught them how to swim,’ says Genevieve Barnaby-Adetoro, of her three stepdaughters, ‘inseparable’ sisters Jane, Christina and Rebecca.

The sisters’ aunt, Ajike Johnson – Auntie Jik to ‘the girls’ – can barely think straight after the stress of the past ten days, but is adamant she is wrong.

‘No, Genevieve, you didn’t teach them, but they would have learned when they were young, before they lived with you. I’m sure they could swim.

‘I remember Jane coming with us to that water park in Bolton when she came to stay. I’m sure she was swimming then.’

We never quite establish the facts about how confident these sisters were in the water, but it hardly matters now.

On Wednesday, May 13, both of these women listened separately to news reports of how the bodies of three young women had been pulled from the sea in Brighton.

It was an awful tragedy, unfolding far away. Genevieve was watching the news at home with her husband Joseph in Uxbridge, west London; Ajike, who lives in Manchester, recalls updates from Sky News pinging into her phone.

‘I just remember thinking, “What has happened here? God bless them, and their poor families.”’

Neither woman knew, for the entire day, that this was their family tragedy, that at around midnight, once the police had gone through the handbags left on the beach, and searched the rental apartment where the women had been staying, there would be police officers on Genevieve’s doorstep, breaking the worst news possible.

Sisters Jane, 36, Christina, 32, and Rebecca, 31 – Jik’s beloved nieces, Joseph’s adored daughters, had entered the sea at some time before 5.30am, in circumstances that are still unclear, and been swept to their deaths.

They were fully clothed, ‘right down to the shoes’ says Genevieve. ‘Not in going out clothes, as was reported, just in ordinary daytime clothes.’

‘The police phoned first,’ she adds. ‘They asked Joseph if he had children, and when he said yes, they asked him their names. Then they came round to tell us in person. We’d been watching the news and had no idea it was our girls. We didn’t even know they were in Brighton. Then we had to go and identify the girls, one by one.’

Genevieve tells me that there is a fourth sister in this now broken family. Her daughter Lilly, 25, technically a half-sister, has been inconsolable since learning that all three are dead.

‘Joseph’s biggest worry was “How do we tell Lilly?”. In the end I did it. We’re all in this nightmare you think you will wake up from.’ She tells me they are trying to get Lilly, who lives in the US, working as a manager for a Dallas engineering company, back for the funeral. There is no date yet, because a police investigation is underway and the bodies have not yet been released to the family.

‘We think it’s right that Lilly is involved,’ says Genevieve. ‘We’ve said she can be in charge of their homecoming and she wants it to be as beautiful as possible, with white caskets and white roses.

‘She even wants a carriage to take them home, to honour them. We will ask her to pick their clothes.’

There is a strong sense that the women of the family will sort this funeral, because the sisters’ father Joseph, a 68-year-old chief security guard, simply doesn’t have that sort of strength right now.

‘They are his babies. He is a softie anyway. My brother is a teddy bear, but when it comes to his girls...’

‘He has been catatonic,’ says Jik. Genevieve agrees. ‘He won’t shut his eyes, he forgets to eat.’

In an almost unbearable twist, this is not the first time this close-knit unit has endured tragedy.

In 2010, the girls lost their mother, Janice Adetoro, aged just 43, in particularly horrifying circumstances that have now taken on an added poignancy.

Janice, who had split from their father and suffered mental health issues, walked into a park lake near her Midlands home on a January day 16 years ago. Her body was not recovered for several months, because of snowy weather conditions at the time.

Jane, Christina and Rebecca – then aged 20, 16 and 15 – did not know for all that time if their mother was alive or dead.

As part of a police appeal for information, Janice’s brother made a direct plea to his sister: ‘The girls are so upset and can’t stop thinking about you,’ the local newspaper report from the time reads. ‘For their sake we need you to make contact.’

‘It traumatised the girls,’ says Jik. ‘They never recovered.

‘They’d been living in the Midlands with their mum, but then moved in with their dad and Genevieve in Uxbridge afterwards. They picked up the pieces.’

Whether this painful chapter in the family history is linked to what happened in Brighton, we may never know. The family have no idea why the sisters were even there, or how they got there. The only connection they can recall with the seaside town is one family holiday.

Police have been investigating CCTV footage to see if they took the train, and try to pinpoint their movements once they arrived.

Was it in character for them just to take off? ‘No. They might go walking but not like this,’ says Jik.

One theory the police will clearly be looking at is whether these sisters walked into the water deliberately, as their mother had done. Genevieve is adamant they could not have.

‘No, no, no. It is 16 years since they lost their mother. Time diminishes pain. It is still there, but there is no way you kill yourself after 16 years because your mother died. It doesn’t happen like that.’

Jik clings to the thought that it was a terrible accident, and an unthinkable coincidence.

‘I pray that they’ve been being mischievous, and that one of them lost their footing and the others dived in to save them.’

The vacuum of information has – as is so sadly often the case – been filled by armchair sleuths and social media conspiracy theorists.

The family has agreed to this interview because they’ve been horrified at how the deaths have captured public attention, some of which has been critical.

‘We’ve had to tell Lilly to stay off the internet because every time she goes on there, she sees her sisters everywhere, and the comments sections are even worse,’ says Genevieve.

‘People have come up with their own explanations of what has happened. I read things like, “Oh, they are blacks, maybe they fell off a boat”, or “three less hijabs”. I’ve read things that have made me cry.

‘People are heartless. Some are saying, “We MUST know. We must have answers.” Hold on a minute. We are their family, and we don’t have answers.’

And my goodness they want them. Jik, 51, a former social worker who now works as a life coach, is almost in tears, partly furious ones; partly just exhausted ones. ‘Don’t think we aren’t asking the questions ourselves. “Girls, why were you in Brighton? Did you just decide to go?” I’ve gone over and over it.

‘That night there was a David Attenborough tribute thing, for his 100th birthday. The girls loved David Attenborough. They used to watch his documentaries. Did they decide to go to Brighton for that? Did they go for a paddle in the sea?

‘It would have been just like them to put their bags down carefully – they all had a touch of OCD and wouldn’t have wanted to get them dirty – and I’ve read that the water drops away suddenly.

‘Did one fall in and the others go to help, because they would have done. Where one of them went, you always found the other two.’

She pauses. ‘My initial thought when I heard was, “Who has done this to them?” because they are so naive, so closed off, in a way, that I thought someone must have done this.’

In the wake of Janice’s death, the family had to recalibrate, each member changed, their dynamic forever altered, and a contained new unit Jik calls ‘the bubble’ emerged. She tells me: ‘Jane became the mother for the girls. She was the disciplinarian; they followed her.’ Genevieve adds: ‘Becky was more of the clown; she cracked jokes a lot. Christina was the stubborn one. If you wanted Christina to do something, you’d have to ask her 20 times.’

The girls were bright, high-achievers who would grow into young women with poise. Jane worked as an accountant. Christina was in education, studying at Brunel University, while Becky had done various courses after school and, Jik says, was forever being teased by her family to buckle down and commit to something.

They had, says Jik, full lives ahead of them. None had a boyfriend or partner, says Jik. She and Genevieve wrack their brains to think if there was ever mention of one, and they recall that Jane was once seeing a handsome man, ‘and we thought it might go places’, but it fizzled out.

None of the sisters socialised much. They attended church, but they didn’t drink.

‘They were teetotal,’ says Jik. ‘If one of the rest of us had a drink or a cigarette, they’d say “Auntie, Auntie!”.’

‘They were unlike other girls of their age. None of them were on social media. They didn’t go out partying. They weren’t into make-up and they didn’t dress in a revealing way.’

The women allow themselves a smile at social media speculation that they would have been clubbing in Brighton. Absolutely, categorically not.

‘If you knew our Jane...’ says Jik. ‘She was always covered, I mean even her arms were completely covered up. But they were proud of being a bit different. They didn’t need to be like other girls.’

‘They didn’t have other friends really – didn’t need them. It wasn’t a negative thing, they just had everything they needed in each other. And they were always together. If you saw one of them, the others would be there, too.’

They weren’t, she insists, ‘recluses’, and when it did come to them leaving home two years ago and moving to a flat in Uxbridge as a trio they were elated.

‘They were excited to be independent, but they were still co-dependent, to a point, with their dad and Genevieve. He still helped them financially, emotionally. He was there for them.

‘They’d speak or message several times a day. Now we have to go into their flat and sort things out. No one can bear that.’

This is a family struggling in the sudden glare of publicity.

Another layer of confusion came when the family provided police with a photograph of the three girls, but it transpired that the image had been digitally altered because they didn’t have one of all three sisters together.

Jik says they are devastated that this diverted attention from their tragedy – and gave the conspiracy theorists more ammunition.

‘It’s been a witch-hunt,’ she says. ‘And our girls deserve better.’

The answers will come, in time. Now they must plan a triple funeral and begin the grieving process.

Is there any comfort in the fact that the three sisters died as they had lived – together?

‘No,’ weeps Genevieve. ‘They didn’t come into this world together. Why would they leave it together? They had their whole lives ahead of them. They should have got married, had children, grandchildren. We have lost so many years. There is no comfort here.’

•  To support the family go to: gofundme.com/f/in-loving-memory-of-jane-christina-rebecca