Rajya Sabha MP Kapil Sibal on Friday congratulated the previous UPA government and the current dispensation over Mumbai attacks mastermind Tahawwur Hussain Rana`s extradition and expressed confidence that it will now become clear who all from Pakistan`s establishment were involved.

The National Investigation Agency (NIA) on Friday began Rana`s questioning here to unravel the larger conspiracy behind the deadly terror strikes of 2008, official sources said.