New Delhi, March 21 -- A day after a special court acquitted Swami Aseemanand and three others in the Samjhauta Express blast case, senior Congress leader Kapil Sibal Thursday sarcastically said with a verdict that "no one knows" who killed 68 people, it must be a "proud day" for the criminal justice system.

Twelve years after a blast on the Samjhauta Express killed 68 people, mostly Pakistanis, a special court in Panchkula acquitted Swami Aseemanand and three others in the case.

"All the four accused, Naba Kumar Sarkar alias Swami Aseemanand, Lokesh Sharma, Kamal Chauhan and Rajinder Chaudhary have been acquitted by the court," NIA counsel Rajan Malhotra had said.

Reacting to the development, Sibal tweeted: "2007 : Samjhauta Express B...