Prosecutors in the Netherlands have charged a father who allegedly held six of his children against their will on an isolated farm for nine years with sexually abusing two of his other children, authorities said Thursday.

The 67-year-old father was previously charged along with a 58-year-old Austrian national with illegal deprivation of liberty and abuse for their alleged role in keeping the six young adults on a farm near the village of Ruinerwold, about 80 miles northeast of Amsterdam.

Police located the father and five young adults during an October raid triggered by a 25-year-old man — also part of the family — who raised the alarm at a local bar. Officers who went to the farm, which was largely obscured by trees and had a large vegetable garden, found improvised rooms where the family lived in effective isolation.

Investigators say the 67-year-old fathered a total of nine children with a woman who died in 2004. Prosecutors allege that he sexually abused two of his oldest three children, who had already left home. Details of when and where the alleged abuse happened were not released.

The father’s identity has not been made public by authorities, but numerous reports in the European media have identified him as Gerrit Jan van Dorsten. In October, the Family Federation for World Peace and Unification, also known as The Unification Church, told Fox News that van Dorsten “was briefly a member of our movement in the mid-1980s,” but added that he “is known to have suffered from mental health issues and left our organization in 1987.”

Dutch media have reported that the father had written extensively online about his self-styled religious beliefs, including a video apparently showing him working out on a home-made fitness machine.

Prosecution spokeswoman Debby Homans told national broadcaster NOS that the father still has not been questioned for health reasons. She declined to elaborate on the health issues, but media have reported that he has suffered a stroke.

Meanwhile, a filmmaker working on a documentary about the case released statements from the oldest four children — the three who had left home and the 25-year-old who raised the alarm — who said that they “recognize” their experiences in the indictment and have faith in the legal proceedings.

However, the younger five siblings stood by their father.

“We have learned from our father to seek happiness in your relationship with God and to take your education into your own hands and we still believe in that,” they said in the statement.

Prosecutors said in a statement that the father and the 58-year-old man will remain jailed as investigations continue. The pair are expected to appear in court in January.

Both men are also accused of holding a 69-year-old Austrian man against his will in the eastern town of Meppel for several months in 2009, as well as money laundering after large amounts of cash were discovered at the farm.

Fox News’ Travis Fedschun and The Associated Press contributed to this report.