During the 26/11 investigation, we could do a much better job of exposing Pakistan's perfidy compared to the 1993 Bombay blasts probe. This was not necessarily because of our success in capturing Ajmal Kasab alive but because we could marshal scientific evidence with American help to nail Pakistan, which was not forthcoming during the 1993 blasts enquiry.
Former Federal Bureau of Investigation (FBI) chief Robert Mueller had given details of this close cooperation when he addressed the Council on Foreign Relations on 23 February, 2009.
After David Headley's story came to light following his arrest in October 2009, there were misgivings in India as to why the US did not forewarn us on his pre-26/11 activities.
But their draconian Intelligence Identities' Protection Act prohibited anyone from disclosing the identity of informants to others, including foreign governments. "Scooter Libby", a close confidante of vice-president Richard Cheney was convicted under this law in 2007 for revealing the identity of a Central Intelligence Agency (CIA) deep cover agent.
But the US did not fail in passing on advance intelligence on 26/11 to us. Our former home minister P Chidambaram had admitted in November 2010 that America had indeed shared intelligence with India in "the months leading to the attacks and thereafter", though Headley's name was not mentioned.
Ordinarily, even within a country, the name of the informer is never revealed while passing on such intelligence.
On March 18, 2010 Headley entered into a 35-page "Plea Bargain Agreement" with the state attorney at the Illinois Northern District Court. He pleaded guilty on three conditions to a dozen US federal terrorism charges, including planning the 2008 Mumbai terrorist attacks.
Firstly he would not be given the death penalty. Secondly, he would not be extradited to India, Pakistan or Denmark. Thirdly "sentencing guidelines" would be followed.
Our previous government was wrong in assuring us that they would try to get Headley extradited to India. The plea bargain conditions are irrevocable. Also no country would agree to extradite an accused before completing his trial and sentence in home country.
On January 24, 2013, Headley was sentenced to 35 years imprisonment followed by five years of "supervised release". So any chance of his coming to India to stand trial would happen only in 2054!
But Headley knew much more about the culpability of Pakistan than what has been judicially known. So the question was how to get his testimony in an Indian court without his physical presence? That is where his plea bargain agreement came in handy.
On March 18, 2010 he had agreed to fully participate in any debriefings for the purpose of gathering intelligence or national security information. He also agreed to testify in any foreign judicial proceedings held in the United States by way of deposition, video-conferencing or letters rogatory when directed by the United States Attorney's Office.
This is what he is now doing. We need his testimony to fully understand Pakistan's conspiracy. This would enable us to mount international pressure on Pakistan. The Kasab investigation and trial had revealed only one dimension.