On Thursday morning, in Chicago, David Coleman Headley is likely to plead guilty in a court where he's being tried for planning and executing the 26/11 attacks in Mumbai in 2008.

In December, Headley said he was innocent when he was formally accused of playing a key role in 26/11 on behalf of the Lashkar-e-Toiba (LeT).

Headley's revised stand doesn't surprise some who say it's in keeping with reports that Headley started out as an undercover agent for America.

Sources say Headley, also known as Dawood Gilani on his Pakistani passport, has been cooperating with American authorities all along, providing them with information about 26/11 and the planned attack on the Danish newspaper that printed the infamous cartoon of the Prophet Mohammed.

Many in America (and outside) question whether Headley's cooperation stems from the fact that he started operating in the sub-continent as an American agent, working for the Drug Enforcement Administration. (Read and Watch: David Headley: Truth & lies)

Has the US decided to let Headley off lightly, in return for information that could well be the key to unravelling other terror networks? Or are they simply protecting one of their own?

The 12 charges against the 47-year-old which range from bombing targets in India to aiding and abetting murders of US citizens could result in a death penalty, but the new deal struck means it's unlikely that prosecutors will seek capital punishment.

So will Headley's lighter punishment be a reward for information that could help unravel some of the world's biggest networks, or are American intelligence officials simply protecting one of their own?

For India, the concern remains whether it will get to question Headley. America has already described India's request for Headley's extradition as "too premature." (Read: Headley plea bargain not a setback for India?)

Given that Headley made 9 trips to India between 2006 and 2009, and surveyed landmarks that have already been attacked, it's critical for Indian intelligence officials to get access to him. But "he is a US citizen and unless he waives his rights to be interrogated by a foreign government the US constitution is prohibited from offering him to the Government of India. So we have done the next best thing. Everything that you want to know we are prepared to ask him, and everything that he tells us we are sharing with you," says Ashley J Tellis, Foreign Policy Expert, Carnegie Endowment for International Peace.

Government sources say that irrespective of Headley's plea deal, India's request for his extradition stands. The government will eventually file a chargesheet against him for his role in 26/11 and other terror-related activities, but the details are still being reviewed.

But if Headley does win a lesser sentence, India's suspicion of him being a double-agent will be confirmed.

"I don't want to get hypothetical on what he intends or what he ultimately will do. We will wait on what he does in terms of his own statement in the trial. We have already stated the position on behalf of India as far as Headley is concerned and I think the Home Ministry is dealing with it. So that is where we stand," said S M Krishna, India's External Affairs Minister.

Making a plea deal is not new to Headley. When arrested on drug trafficking charges in the past, he provided so much information about his Pakistani suppliers, that he was sentenced to less than two years in jail. Prosecutors have declined to comment on what deal has been negotiated this time round.