A Kalpetta police station official said all the six attackers were recognized through identification parade.
"The youths have been arrested and now they will be presented before a magistrate. A case has been registered against them," said the official, who did not wish to be identified.
The girls had been subjected to sexual exploitation since January this year, the official added.
Lok Sabha member from Kannur PK Sreemathi, who held an interaction with the victims on Tuesday, told reporters that the accused had shot photographs of the victims and were threatening them with the leaking of the same. The girls were left with no other option but to fall into the trap.
He instructed the authorities that all the residents of the orphanage be given proper counselling for their sound mental health.
Office-bearers of the orphanage told the media that the moment they came to know about the incident and realized the horror the girls had been through, they reported the matter to the police. The police acted promptly and the six people were caught behind the bars.
State Minister for Social Justice KK Shailaja told reporters in the state capital Thiruvananthapuram that very soon all the orphanages would be thoroughly inspected to make sure the inmates are in a proper condition.
"Strict action would be taken against the violators of rules and regulations," said the minister.