The public prosecution department is carrying out dna tests on the six young adults found living on an isolated farmhouse in Drenthe earlier this month, to find out if they are actually related to Gerrit Jan van Dorsten, who is said to be their father.

Van Dorsten is due to appear again in court on Wednesday for a new remand hearing, as is odd jobs man Josef B, who rented the farmhouse where the group lived. Both are being investigated for holding the others against their will, endangering their health and money laundering.

The children have reportedly said that Van D is their father, but none of them are included in the Dutch national register, so it is unclear if they actually are related. The mother died over 10 years ago.

Van Dorsten is known to have had three older children who broke contact with him in 2011 and moved in with other relatives. They are said to have been unaware that he had other children, local paper Dagblad van het Noorden said.

The family were discovered earlier this month when one youngster went to the local bar, appealing for help. They are thought to have lived on the farm for nine years.

At the time the family was portrayed as some sort of doomsday cult with no connection to the outside world, but it emerged later that both the father and the eldest son were active on social media.