It is not yet clear whether Kuldeep's release has been secured by paying ransom to the militants.
The United Liberation Front of Asom has kidnapped the son of a Bharatiya Janata Party leader from Assam and demanded a ransom of Rs. 1 crore.
On the Islamic State-style video sent by the ULFA-I to TV news channels, the DGP said it was the first time that such a video has been received.