Keys were left in the ignition. Doors were wide open. Mobile phones and wallets lay scattered exactly where they were left.
On an ordinary August day in 2016, a successful farming family of five fled from their 40ha redcurrant farm in regional Victoria embarking on a bizarre 1500km road trip.
They were not running from an intruder or a crime syndicate, they were running for their lives — or so it appeared.
For the past decade, the disappearance of the Tromp family has remained one of Australia’s most unsettling mysteries.
The fleeing of the Tromps eventually leading to their separation and recovery amid a shared psychotic episode.
The mysterious event captured global attention, becoming a frequent subject of international media, true crime podcasts, and psychological case studies.
Theories gripped the nation, one of which is folie en famille — a historical term for shared, fixed delusional beliefs within a family — which a psychiatrist suggests may offer an explanation.
While the Yarra Ranges family eventually returned to ordinary life, the events of the six days they were on the “run” remain shrouded in silence.
Attempts to revisit the story in Silvan have often been met with resistance.
During this reporter’s recent trip to Silvan, neighbours made it clear that we — and any questions regarding that fateful week — were not welcome.
The frantic journey north
By all accounts, the Tromps — Mark, 51, his wife Jacoba (Coby), 53, and their adult children Mitchell, 25, Riana, 29, and Ella, 22 — were a normal, hardworking family running a successful berry farm that they had operated since 2006.
Coby, a former teacher, had taken a leading role in running the farm while her husband, Mark, focused on his earthmoving business.
Redcurrants have been grown at Parkview Farm, nestled on the corner of Chapman and Parker roads in the picturesque town of Silvan, 60km east of the city, for more than 20 years.
On August 29, 2016, the Tromp family’s lives changed forever, embarking on a paranoia-fuelled road trip believed to have originated from Mark who believed they were being followed and in danger.
Sergeant Mark Knight said at the time, there was no one standing over the family, and the Tromps did not have crime links or know of anyone out to harm them.
“We can categorically say there was no one following any of them,” Sergeant Knight said.
“There has been no physical threat to this family at all. It was in their minds.”
Without warning, they fled their Chapman Rd home in Ella’s grey Peugeot station wagon, leaving behind all other cars with keys still in the ignitions.
They took a large amount of cash but left behind essential items like bank cards, passports, and all but one of their mobile phones.
This masthead had reported Mark and Coby had insisted all phones and tablets be left in their unlocked house.
The family’s erratic journey began with a drive north toward NSW.
Approximately 32km into the trip, near Warburton, Mitchel threw his mobile phone — the only one the family had brought — from the car window.
This act was widely interpreted by investigators as a sign that the family believed they were being tracked.
Professor Suresh Sundram, Chair of Psychiatry at Monash University said it could be said the family suffered from “folie en famille.”
Translated to family madness, Professor Sundram said, “this is a psychosis that has affected a number of members of a particular family that share a set of beliefs which are false.”
“They are fixed in the sense that people really truly believe them, and they’re not really shakable.
“Even when you present people with evidence to the contrary in a psychosis, they won’t incorporate that new evidence to change or shake their preformed beliefs.”
It was against this backdrop of escalating, unshakeable fear that the family’s frantic journey continued, driving them further away from the life they knew.
Eight hours later on August 30, the family unit of five reached Bathurst, NSW, the last destination they would be at together.
The slow return
Alarmed by his family’s rapidly deteriorating state of mind, Mitchell separated from the family about 7am from Kelso, embarking on his journey back to Victoria.
Mitchell later told the media he didn’t feel in danger despite his parents’ erratic behaviour.
With this information, Professor Sundram suspects Mitchell did not share the same delusions the other family members were.
“Clearly, he was somebody who was questioning whether this was true or not true, and that’s the reason why he took the phone,” he said.
“It sounds like that maybe he was coerced into throwing the phone out, or that that was done against his will.”
Shifting the focus to the potential source of this shared psychosis, Professor Sundram further hypothesised that Mark and Coby were the originators of the belief.
“It’s unclear which parent it was because they were a relatively isolated couple living in a relatively isolated setting,” he said.
“They start to consolidate and assume their own reality and so I suspect that potentially may have happened with this family.”
Following the abandonment of Mitchell, the remaining members continued towards the Blue Mountains, where more family members split.
Near Jenolan Caves, Riana and Ella left their parents, allegedly stealing a ute, which Ella drove towards Goulburn.
The girls were both charged with theft of a motor vehicle but later the charges were dismissed under the NSW Mental Health Act.
It was in this regional NSW town where both sisters separated from each other and Riana’s journey took a distressing turn of events.
While Ella drove the stolen vehicle back towards Silvan, Riana was found hiding out in the back of a stranger’s ute.
Keith Whittaker drove several kilometres when he felt a kick behind his seat, turning around to find Riana in a terrifying state.
He told the Goulburn Post she was in a “catatonic state” and unable to identify herself and where she was.
Professor Sundram suggested that Riana’s state of mind could have stemmed from a deep conflict of beliefs.
“It’s possible that maybe that individual was so conflicted between what they, on the one hand, assumed to be the true reality versus, on the other hand, what their family members were telling them to be true,” said Prof Sundram.
“That level of internal conflict caused them to not be able to respond appropriately.
After calling the police, Riana was taken to the Goulburn Hospital where she was treated for stress related issues.
It was this afternoon Mark and Jacoba were both reported missing, sparking police to attend the abandoned family home in Silvan, where Ella arrived that night.
Ella said she and her family “weren’t thinking clearly” when they set off.
“The general stress of life just got a bit too much,” she told this masthead.
“Our minds weren’t in the best place. I still feel confused. There is no one reason for it. It’s bizarre.”
When authorities arrived, the scene was bizarre and appeared to be a snapshot of a life interrupted.
It was not the scene of an orderly departure, but more of a panicked escape.
On the morning of Wednesday August 31, Mitchell returned home catching the train from Sydney.
Meanwhile Mark and Jacoba had driven back over the Victorian border to the town of Wangaratta where Mark remained while Jacoba travelled north to Yass where she was found in an agitated state.
She was taken to hospital and assessed by doctors who deemed her mental health as “poor”.
A local couple later reported a disturbing encounter with a man believed to be Mark, who tailgated them in a silver Peugeot station wagon before fleeing into a park.
On September 1, Mitchell appeared on Channel 9 alongside police in an effort to locate his father, telling the media his parents were “fearing for their lives,” though he could not explain why or who was behind the paranoia.
Two days later, on September 3, Mark was found running along the streets on the outskirts of Wangaratta.
While being driven away by police, he gave the waiting media his middle finger.
The father of three issued an apology for the “hurt and concern” caused by the week-long journey which gripped the nation and the globe.
He said he hoped he and his family can “begin to make sense” of the ordeal, and will be receiving help from mental health professionals.
“In recent days, my family has been through a difficult period,” he said.
“We will soon be reunited and together. I hope that we will begin to make sense of our ordeal and return to a normal life.
“I am conscious of the burden these events have placed upon our extended family, friends and the community resources devoted to our aid.
“Without reservation, I apologise for the hurt and concern caused by these events.”
Mark underwent a mental health assessment in hospital with the support of Coby and his parents George and Wilma, who said their son’s behaviour was totally out of character.
“It’s not like him at all,” Mrs Tromp said.
“We really don’t know what has triggered all of this. We are just really overjoyed that Mark is safe.”
He said he didn’t believe they were under financial strain or aware of any mental health concerns.
“There’s no sinister, no cult, no one else involved, that’s why this is such a puzzle,” he said.
“I can understand why everyone is so intrigued. One day we’ll know.”
But more than 10 years on, the mystery remains.
Mystery remains
A decade later, the Tromp family remains silent.
Ella told this reporter it was “private and confidential”, while Mitchell suggested we “get a new story” and Mark declined to speak with us.
One woman staying with her cousins on a neighbouring property on Chapman Rd said the “close-knit community” would not discuss the past.
“Whatever happened has been and gone and that is their business.”
Another neighbour who wished to remain anonymous said in the few brief conversations they have had with Mark, he was deeply embarrassed by the events which transpired a decade ago.
The family never provided the eagerly waiting media with any explanation for the events of the week and appeared keen to get back to the life waiting for them on their berry farm.
Theories continue to circulate but the definitive truth of what happened on that farm in Silvan remains just out of reach.