The Austrian handyman accused of holding captive a family of six in the basement of a Dutch farmhouse for nine years once belonged to a cult and believed he was better than Jesus, his brother claims.
Carpenter Josef Brunner, nicknamed Josef the Austrian, has been arrested for allegedly imprisoning his friend and his five children in a remote farmhouse at Ruinerwold, 60 miles north of Amsterdam.
The van Dorsten family were discovered after the eldest son, 25, walked to a nearby bar on Sunday, ordered five beers, and asked for help.
Brunner met the reclusive father-of-five Geert Zon van Dorsten at the bizarre sect he joined after he dropped out of the Army in the late 90s, according to his brother.
Franz Brunner says his 58-year-old brother was delusional and became estranged from his family after joining the sect.
'My brother was always only for his own advantage,' he said. 'He was with a sect and he believed he was better than the Jesus.'
'When my father handed over the farm to me, the problems started. When Josef learned that I was in charge of the farm, he immediately demanded that I pay him for his services.
'For ten years, I have had no contact with him. The last time I saw him I said to him, "You do not have to come back. I do not want to have anything to do with people like you."'
Detectives are trying to unravel what drove Austrian-born Brunner to detain van Dorsten and his children, aged between 18 and 25, in a secret room at the secluded mansion.
To those who knew him for the 16 years he lived in the Netherlands he was a secretive, quiet loner who rarely made friends and found it difficult to engage socially.
His brother Franz said the kidnap suspect had abandoned his twin daughters when they were young children and ignored them when they tried to contact him as adults in 2017.
When Brunner's father died in 2015 he did not attend the funeral and when his mother passed away 18 months ago, he failed to return calls to his family in Austria.
Franz said Brunner was born on March 3, 1961 in Waldhausen, Austria and was one of five peasant children.
He completed a carpentry apprenticeship with distinction, but while enrolled in the army in Linz he joined a sect.
The brothers quarrelled over their parent's farm and fell out with Brunner moving out.
Josef camped for a while in a house nearby and eventually moved in with an old aunt who lived in a 300-year-old house with a lot of land in Pabneukirchen, Austria, and appointed him as her heir.
He lived there from 1998 to about 2008, his brother says. He is then believed to have moved to Hasselt, the Netherlands, where he lived next door to the family he is accused of holding captive.
A former neighbour told MailOnline Josef lived briefly next door to the van Dorsten family but had left by the time Geert's wife had died from colon cancer.
Former neighbour Sandra Soer said: 'The majority of children born in this house. There was no midwife involved. They all did that themselves.
'A daughter had a birthday on the same day as my daughter. They often played together. But only in their back garden. The children never went out on the street or came to our house. You'd often see them climbing in the trees.
'The children didn't go to a school in the neighborhood. But I saw them leave every morning with a bag with their father, so I assumed they were going to school somewhere else.'
Mrs Soar said Brunner only lived in the street for a very short time. She said she thought he knew the reclusive van Dorstens before he moved in because shortly afterwards they removed a fence that separated their back gardens.
But by 2004, before Geert's wife died in mysterious circumstances, he had already left.
It is reported that after leaving Austria, Josef fathered up to five more children and is reported to have an adult son living in Zwartsluis, a few miles from the farmhouse where the family were found.
Mrs Soer said: 'One day Gerrit-Jan came and told me that his wife had just died of colon cancer. Nobody knew she was that sick. No one knew when she was buried.
'Not long after, the family had left but they continued to pay the rent for the house. One of the daughters lived in the house for a while. I think she was sixteen. But a short time later when someone from the housing association came round, the house was vacated.'
Mr van Dorsten and Brunner both shared a passion for woodwork. He was a toy maker and his eventual captor built wooden canoes.
Brunner only lived at in the ground floor of the house at de Weerd in Hasselt for a few months and disappeared.
Ms Soer went on: 'I was surprised that they had remained in contact and even more shocked when I heard what had happened to Geert and his family.
Josef was never friendly. He never said hello. He wasn't friends with anybody.
'He never had a wife. He never had a girlfriend. He would never go to a bar. He was just mysterious.
'When they left, I didn't know where they'd gone.
'It was a total surprise to me that they were still in touch with Josef. This is a very sad situation for the family.'
Van Dorsten owned a toy shop and moved over the years into rented properties in the village in Zwartsluis before moving into the rented detached house at Ruinerwold which has been sealed off by police.
The van Dorstens allegedly lived like hobbits in the basement of the remote farmhouse for almost a decade before their secret was exposed this week when the eldest son walked into a bar and told the owner how the family had been living.
Jan Zon van Dorsten, 25, drank five pints of beer in the café De Kastelein and revealed to the owner Chris Westerbeek how they had been living.
Neighbours said they had been suspicious about Brunner who would go back and forth from the house to his workshop 15 miles away in a Volvo every day.
Meanwhile MailOnline can reveal how Brunner lived illegally in a trailer four miles from the house where the family of six were imprisoned.
The caravan was parked behind his workshop at Meppel.
He would make weekly visits to a local Lidl supermarket in to stock up on supplies for the family.
A man who owns a building business next door said: 'I have known him for about seven years, but I really know very little about him.
'I would see him every day, but he will just say hello. Only wants to look inside his work premises and I saw a trailer hidden behind a wall where he was living.
'I could never have imagined that he had another home and six people were in there. He never ever talk about friends or anybody.
It is not allowed for him to live here, but he used to.
'I was curious because he would buy something like 50 toilet rolls and huge boxes of food once a week and then drive off with them. But he lived here. So he wasn't living with that family.'
Another man, a truck driver, said: 'He was always very secretive. He never spoke with anybody.
'He would reverse his blue Volvo onto the drive of his workshop, and then go inside for the night. Nobody knew him. He didn't want to speak to anybody.'
Brunner, known as 'Josef the Austrian' will appear in court on Thursday, as it emerged the family can barely talk and speak in a 'fantasy language' after spending nine years in isolation.
Investigators earlier revealed they had difficulty understanding the victims, with parts of their speech deemed 'incomprehensible' - and said they slept and ate on the floor in a room with no windows, according to local reports.
Despite sharing a 'small, enclosed space' with no natural light, police confirmed the family were not malnourished and looked 'normal'.
Investigators admit they are still deeply puzzled by the case and are still working to answer key questions - such as whether the family were held against their will by Brunner.
However more details may emerge when he appears in court for the remand hearing, after being charged with the deprivation of liberty and prejudicing the health of others.
Neighbours told local media they were puzzled by the man - described as a skilled 'wood-worker' - as it emerged the 'odd-jobs-man' had asked neighbours for renovation tips such as laying concrete and appeared to have renovated the isolated home alone.
He would reportedly ask locals for tips on building and construction but would not elaborate on where he lived or with whom.
One local told Bild newspaper: 'The man has renovated all this alone, came with his trailer and building materials. I've always wondered 'how can he do it all on his own?'
'He must have had help, it can not be done on his own.'
Residents also claim Brunner had surveillance cameras around the property, kept the gate locked and peered through binoculars.
He would reportedly 'chase' people away that strayed too close to the house.
'It was enough for you to come near the farm and he sent you away. He followed everything with binoculars,' one local told Aftonbladet.
The mystery is deepened further by the fact that Jan, the eldest son, had access to social media and had been active on Facebook since June this year.
Posts on his public profile show he used the platform for several years until 2010, when he posted saying that he had moved to Ruinerwold - the village where the house is located.
The profile then goes silent until June this year, when it suddenly reactivated with a post announcing that Jan was working as an online store manager at Creconat, located in Meppel - a village around four miles from Ruinerwold.
'Creativity for everyone!' the post says.
Jan spent his time on social media posting pictures of nature and promoting causes, such as climate strikes.
On Saturday he uploaded three photos of landmarks around Ruinerwold that were taken in the dark. It is thought these were taken while he was walking to the bar.
It is reported he went to the bar three times before the barman - Chris Westerbeek - called police, describing Jan as dishevelled, confused and needing help.
None of Jan's family were registered on government databases, police have confirmed - perhaps indicating how they managed to go undetected for years.
Local media reported Brunner was born in Vienna. The Austrian Ministry of Foreign Affairs could only confirm that Josef has requested not to be contacted by the embassy, and has refused their help.
The house itself was set back 200 yards from the nearest road, and another 100 yards from the nearest building.
Pictures show it was surrounded by trees, blocking off the view, and also had a perimeter fence.
Vegetables were being grown in plots surrounding the property, while a goat was also kept there.
Ruinerwold mayor Roger de Groot told a press conference that neither he nor the police had ever seen anything like it.
Speaking about the inside of the house, he added: 'The police found a number of rooms with makeshift furnishings where the family lived a withdrawn existence. That is where the six were found.'
He denied that the family had been living in a basement.
A statement from local police said Brunner was refusing to cooperate with the investigation but was detained and being interrogated.
'We understand that everyone still has many questions,' a police spokesman said. 'We do too. That is why we want to do our research thoroughly and carefully.
'This means that we may not be able to answer everything immediately. Simply because sometimes we don't have answers yet. Or we cannot share them.
'We have called in a Large Scale Investigation Team (TGO). Investigators are probing possible criminal offenses under the leadership of the Public Prosecution Service.'
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