Deal with Headley worth it, says US Attorney

"I am convinced that we would have made a terrible mistake if we did not sit down with Headley and get all the information that we did and came from them," US Attorney Patrick Fitzgerald told reporters after a Chicago court convicted Tahawwur Rana on two terrorism charges based in part on Headley's cooperation with prosecutors.

"Headley had an insider's view of what (Illyas) Kashmiri was up to, what they discussed and what he was planning. He had the insiders view of what Sajid Mir was up to, what Major Iqbal was up to and what people were doing," Fitzgerald said, adding that Headley has so far named 34 different targets that had been surveyed.

When asked how valuable was the information provided by Headley, Fitzgerald said that it was well worth it to take the death penalty off the table and agree not to allow him to be extradited to either India, Pakistan or Denmark to face related charges.

"We would be crazy, if we sit around and say, you know what, it was all about Headley and all we want to do is put him in jail and sit around and let attacks happen. And one thing we fully appreciate from the law enforcement realm that we are working with our partners in FBI and intelligence organizations that we need information the American government, the Indian government needed, the Pakistani government needed the Danish Government needs it," he argued.

"We had the chance to take criminal charges holding people accountable and still hold them accountable and use that to get information that we can get to try to make sure that we take out of circulation other people are posing danger, we are going to do this every time," Fitzgerald said.

The US came under fire in India for a plea deal reached with Headley, who used his western appearance and US passport as a cover while carrying out surveillance ahead of the 2008 attacks in which 166 people were killed, including six Americans.

"I have no doubt in my mind the information that we obtained, was processed, was something that was very important and extremely valuable and we are very comfortable with the deal that we made because we had to because it is too important that we do everything we can do to save lives," he said.

"I think, sometime we have to step back and realise what would have happened if Headley was not arrested by the FBI in October 2009 and had made it overseas, he could have continued what he was bent on doing which was to help Illyas Kashmiri, a very very influential terrorist leader linked to al-Qaeda, carry out an attack where they would gone into a newspaper in Denmark and effort was to kill people chop off their heads and throw them out of windows," he said.

"Given the background of people involved it would have been real. So that arrest we believe may well have prevented this serious terrorist attack. And Rana is held accountable for that role, in addition to his role in helping Lashkar," he said.