A Dutch man accused of sequestering his family in a farmhouse for nearly a decade is suspected of sexually abusing two of his children, prosecutors said Thursday.
The two children were not among the six living on the farm in the village of Ruinerwold at the time and had previously left home, the Dutch prosecution service said.
Prosecutors also confirmed that the suspect was the father of all six of the children who were being kept on the farm at the time of his arrest in October.
"In addition to money laundering and deprivation of liberty and mistreatment of his nine children, the 67-year-old man is also suspected of sexually abusing two of his three oldest children," the prosecution service said in a statement.
"DNA kinship research has shown that the six children from the farm in Ruinerwold have the same father and mother and that the 67-year-old suspect is the father," it said, adding that the mother died in 2004.
The Dutch suspect and an Austrian man were both arrested in October and remain in custody.
The family was first discovered when the oldest son still living on the farm walked into a local bar in a confused state and raised concern about the welfare of his other siblings.
Police then went to the farmhouse and found the other five children locked in a small room.
In a further twist to the case, the prosecutors added that the Dutchman and the Austrian had held another Austrian man, aged 69, captive "for several months" in 2009.
"More details will not be shared about the case. The investigation is still in full swing," the prosecutors said.
Both suspects and the family were all part of South Korea's controversial Unification Church, dubbed "Moonies" after their late founder Sun Myung Moon, Dutch media have said.
The Universal Peace Federation, the name the church now goes by, has confirmed that the father of the family was a member in the 1980s before leaving for Germany where "we lost sight of him".