With the Tawwahur Rana trial on in full swing at a court in Chicago, the biggest challenge that would be before the National Investigating Agency is to nail the link between him and David Headley.
"There is an absolute need to link the connection between the two of them in order to have a foolproof case," said an NIA source.
"We are studying the developments every day, and are waiting for the trial to get over before we could question him. Headley's testimony and our own investigations have given us enough material to nail the connection between the two," he added.
"While Headley's testimony does confirm our doubts about the relations between the two, we still need more material to put a watertight case together," he added.
"As we said before, the details that are emerging now are not new to us. Hence, we are waiting for Rana, as we he not interrogated him yet," he said.
To achieve this, the NIA would need a lot of help from their counterparts in the United States and hopefully from Pakistan. "However, we have made several requests to Pakistan regarding this, but to no avail," the source said.
The NIA is interested in seeking voice samples from both the countries. This is the most important aspect of the investigation, since both Rana and Headley reported to the same handlers, and were part of the same module that carried out the attacks in Mumbai.
So, the voice samples will automatically become a strong document in a court of law, when the case gets underway in India. Apart from this, the NIA has also been examining how both Headley and Rana coordinated with each other and corresponded with the Lashkar-e-Tayiba and the Inter-Services Intelligence.
"The Federal Bureau of Investigation will play a crucial role in acquiring these, and India will pitch for an enhanced cooperation with the US during the forthcoming talks next month," the source said.
While an independent investigation by the NIA would be absolutely necessary following their interrogation of Rana, the testimony the duo will be of great value when the case is tried in India.
The investigating agencies would rely on Section 27 of the Indian Evidence Act of 1872 which states, "Provided that, when any fact is deposed to as discovered in consequence of information received from a person accused of any offence, in the custody of a police officer, so much of such information, whether it amounts to a confession or not, as relates distinctly to the fact thereby discovered, may be proved."
According to legal experts, this would essentially mean that his testimony which has been done under plea bargain comes within the ambit of section 27 and is admissible in a court of law in India.
Moreover, when the case is tried in India, it would have large ramifications too. His testimony speaks of the role played by the ISI and its big players, and also members of the LeT.Considering the fact that section 27 would be in play, this means that the names mentioned by Headley could be brought to trial.