Though the group was yet to be identified, senior police officials did not rule out the involvement of National Liberation Front of Tripura (NLFT).
"There is a possibility that the Tripura insurgent outfit might be responsible and the involvement of the Chakma group - Shanti Bahini - was also remotely possible," the official said on condition of anonymity said.
The six people were abducted by 20 to 25 people wearing black suits and armed with Kalshnikov rifles after forcibly taking Rs2 lakh in cash.
Police suspected that the militants were hiding the hostages inside the Bangladesh jungle where many insurgent groups were having hideouts.