A second man has been arrested in connection with the family of six who were discovered on Monday, after being locked away on an isolated Dutch farm for nine years.

He faces charges of deprivation of liberty, abuse and money laundering.

"We arrested the father," confirmed a police spokesperson on Thursday evening in Assen, the capital of the Drenthe region in the east of the Netherlands.

The second arrest followed a Dutch court extending the detention period of the first suspect, Josef B., following an appearance in court on Thursday.

The 58-year-old Austrian, who was renting out the property, faces charges of deprivation of liberty. The judge also decided to extend his detention period to give investigators more time to gather evidence.

Specialist detectives searched the property

Specialist detectives were deployed to examine the property, which lies hidden behind hedges and bushes in the small village.

"We searched through all the rooms digitally to build up a comprehensive picture" the police said on Thursday.

The five siblings aged between 18-25 years were discovered after one of the siblings escaped and alerted a local barkeeper.

It is thought that they had been living in small, makeshift rooms on the farm since 2010.

It is still not known why the family did not leave the farm and whether they were being held against their will. Previously, Josef B's brother had told local press that the landlord was a member of a religious cult.

kmm/msh (dpa, Reuters)