Five women working for a charity in Khunti district, in eastern Indian state of Jharkhand were abducted and allegedly gang-raped at gunpoint, police said on Friday.
The women alleged in their complaint that they were performing a play to raise awareness about human trafficking in the largely tribal Khunti district on Tuesday when they were abducted.
The assailants shot videos of the attack and threatened the women if they went to the police, they said.
The women worked for the non-governmental organisation Asha Kiran which is supported by a local Christian missionary group, police officer Rajesh Prasad said.
"We have been questioning several people," Prasad added.
Police have also rounded up some supporters of Pathalgadi, an anti-establishment self-rule movement popular in several tribal villages.
Pathalgadi supporters resent outsiders and do not allow them to enter or settle in their area.
Khunti is also a hotbed of Maoists, who have been waging a decades-long insurgency mainly for land rights.
Prasad said the women had undergone medical tests and that police were awaiting the results.
Jharkhand has especially been in the spotlight after three teenagers were raped and burnt alive in separate incidents last month.