Cathy McDougall freezes every time she hears that police have found a body.

Every unidentified woman, every unknown child could be her daughter Chantelle, or her six-year-old granddaughter Leela, who went missing 10 years ago from the tiny timber town of Nannup, 200km south of Perth.

“Every time I hear that a body has been found, it’s so hard, my heart misses a beat,” she tells the Guardian.

The most agonising time was in 2015, when a long-decomposed child’s body was found in a suitcase dumped on a remote South Australian highway. It wasn’t Leela.

“Then there was that sighting of a girl in Rome, who spoke English, but didn’t know who she was. They thought it might be Leela, grown up,” she says.

“But it wasn’t.”

It was hoped a long-awaited inquest this week, into the suspected deaths of Chantelle McDougall, 27, and Leela, 6, together with McDougall’s partner (and Leela’s father) Simon Kadwell, 45, and their flatmate Tony Popic, 40, would solve one of Australia’s most mysterious missing person cases.

Chantelle and Leela McDougall

Instead, what emerged was a dark tale of a strange and controlling doomsday cult leader, international identify theft and a feared suicide pact.

As Detective Senior Sergeant Greg Balfour told the court, “(the inquest) probably poses more questions than it answers”.

What is known is this. In 2007, all four lived in a blue, rented weatherboard house on a beef farm, about 11km out of Nannup. Their lives were dominated by the strange spiritual beliefs of Kadwell, who believed the world as we know it was about to end, and prepared souls would ascend to another plane. He stayed up all night chatting to devotees online.

Chantelle McDougall had told her mother they were headed to Brazil, “to prepare the world for a new divine plan”. Kadwell, she said, was already there. She sold her car and her beloved dachshund dogs and their puppies. She told no one else, but left a brief note for her landlords. She left the house spotless.

After that, apart from a few tantalising glimpses, it is as though they left the face of the earth.

‘He had some power over people in that house’

Landlord and beef farmer Anne Crouch visited the old blue house often, and described Chantelle McDougall as the “hardest working person in that household”. Kadwell was up all night on the computer and slept all day.

Simon Kadwell aka Gary Felton

She described McDougall as an outgoing and immensely practical young woman who was working as a part-time barmaid, a swimming teacher and at the fish and chip shop. Popic, who was gay, worked at a local hardware shop, and was also well liked. Describing them as ideal tenants, she remembers they paid for the carpets to be changed.

“The karma of the carpet wasn’t to their liking,” Crouch said.

But she said that while Kadwell was clueless when it came to practical matters, he clearly dominated McDougall and Popic.

“I’d meet her out with Leela, and she’d say she couldn’t go home, as Simon had ‘clients’. I’d see her at a park and wonder if Simon had ‘clients,” Crouch told the court.

“He had some power over people in that house … but I don’t think he killed them.”

False identity and false leads

Balfour said Kadwell was a fake. He was really Gary Felton, born in the United Kingdom in 1962.

A “self-styled shaman”, he had taken a work colleague’s birth certificate, got a new UK passport and fled the country. He began a new life, travelling through the US and India, where he met an Australian woman named Deborah in about 1993. In an eery similarity to the current case, Deborah’s parents also reported their daughter missing, before tracing the couple to an Indian ashram.

The couple later moved to Melbourne, where Kadwell, then 35, met McDougall, a fresh-faced 17-year-old from country Victoria. McDougall moved in with him and Deborah and their young son, Daniel. About the year 2000, they moved to Western Australia, where they set up a house in the beachside suburb of Floreat. Another “follower” of Kadwell moved in, a young woman called Justine Smith. McDougall gave birth to Leela in 2001.

When that household fell apart, amid bitter recriminations and ill-feeling, Kadwell, McDougall and Leela left the big smoke. Their friend Popic, a gentle nature-loving country boy from Northam and Manjimup, later joined them in Nannup; population 500.

Tony Popic worked at a local hardware shop and was well liked

Just before the disappearance, there were signs Kadwell’s false identity was about to be unveiled.

An aggrieved former boyfriend of McDougall tipped off local police that Kadwell might not be who he seemed. At a routine traffic stop, the police questioned him briefly. A few months later, the four were gone.

Police contacted people in Brazil as well as the UK police, and emailed ashrams in India, but to no avail.

The trail went cold until about 2013, when it was revealed that police suspected either Popic or Kadwell had used a fake name to travel on bus and train routes spanning from Northcliffe, a forest town 350km south of Perth, to Kalgoorlie, about 600km east of Perth, on 16 July 2007. No one knew their final destination.

A Domino’s Pizza delivery driver also reported delivering to a man matching Popic’s description at a remote spot in Perth’s Kings Park, late at night on 15 July 2007. The park was never searched.

Mass suicide?

Criminal behavioural psychologist Dr Kris Geisen told the court she believed McDougall, Popic and Leela were probably dead and had killed themselves in their attempt to reach another spiritual dimension. The Brazil plan was a ruse.

But she wasn’t so certain that Kadwell – whom she described as a “narcissistic conman” – wasn’t still alive and living under a new name.

“I am fairly confident that Chantelle and Leela, are no longer with us, followed by Popic,” she said, noting the bodies were probably still in Australia, and Popic and McDougall had somehow managed to conceal their suicide.

“With Felton [Kadwell], I’m a bit more ambivalent. We can’t ignore his history where he had concealed his identity before. It would not be difficult for him to change his identity and start again. That’s a possibility.”

She noted that two Canadian backpackers, devotees of Kadwell, had killed themselves in July 2007, after making a visit to Nannup, the inquest heard, which was consistent with her understanding of Kadwell’s spiritual beliefs.

Kadwell had also once written to a friend in the US, telling her of a “suicide pact” with Popic. Kadwell planned to take lethal drugs, and administer them to McDougall and Leela. Popic would bury the others and then kill himself, according to police evidence. But Kadwell went cold on the idea when his friend told him it would be tantamount to murdering Leela.

But Geisen says Kadwell was so narcissistic, and so detached, that ultimately, that may not have mattered to him.

Still alive?

Others believe all four might still be alive.

“You were discouraged to make contact with family. Chantelle stood up to that, she still had very, very strong contact with her mother,” Smith, who was once in love with Kadwell, told the inquest via video link.

She rejected the idea that Kadwell had killed the others, or that he killed himself.

“I think it’s more likely they would be hiding, as much as I knew them,” she said.

An age progressed photograph of Leela McDougall released by the Australian federal police this year. Photograph: AFP

Smith had been an ardent follower of Kadwell’s spiritual beliefs, before breaking free.

She followed him from Australia to the UK, then back to Floreat, where she shared a house with him, Fleischer and McDougall.She described it as being similar to a cult.

“It seems strange they would hide a suicide. It’s not beyond belief they would want to go into hiding. If there was something he was running from, that someone had worked out his real name. That seems more likely to me,” she said.

Even the coroner Barry King said it would be “very difficult” to be able to exclude the possibility that at least some of the four were living somewhere else under assumed names.

‘We’ll never give up’

The Popic family released a statement at the end of the inquest on Friday, , grieving their gentle brother and urging other vulnerable people to “turn away from self-proclaimed prophets”.

Jim and Cathy McDougall say they’ll never give up the search to know what happened to Chantelle and Leela.

“Often, I think they have gone into hiding, but then another day I think, maybe something’s happened to them,” Cathy McDougall says, adding that she’s prepared for the prospect they may be dead.

“How can four people just vanish?”

• Crisis support services can be reached 24 hours a day: Lifeline 13 11 14; Suicide Call Back Service 1300 659 467; Kids Helpline 1800 55 1800; MensLine Australia 1300 78 99 78; Beyond Blue 1300 22 4636