Official sources said though the foreigners were carrying Taiwanese passports, it is being examined whether these travel documents are genuine or fake.
Investigators are also baffled over the fact that the the foreigners are living in one of the remotest and inaccessible corners of the country and so far have not been able to explain the source of Rs 30 lakh and USD 3000 found with them.
"There has to be something more," a source said.
The owner of the house where the foreigners were found is a man from Sikkim and he is being questioned on his links with the eight arrested people.
The probe agencies are also trying to find out how a person from Sikkim could buy land and built a house in Himachal Pradesh where non-Himachalis are barred from owning lands.
"The Sikkimese person has been under the observation of intelligence agencies which led to the arrest of the eight people," the source said.
