With David Coleman Headley's travel itinerary and the persons he met up with during his nine visits to India becoming increasingly clear, investigators believe that the Pakistan-born American, now in US custody, could have played a role in planning the Mumbai terror attacks.
Top intelligence officials said Headley, a Lashkar-e-Taiba (LeT) suspect, is now turning out to be one of the prime suspects in the probe into 26/11 - India's biggest terror attack whose first anniversary will be observed in a fortnight - and was also looking at other potential targets in the country.
"Look at the reconnaisance missions he carried out. Why do you think he was travelling to Kochi, Ahmedabad, Pune, Mumbai and Delhi? Clearly it was not for sightseeing," a senior intelligence official told IANS on condition of anonymity.
Investigators say that Headley could well be the missing link in the 26/11 conspiracy.
Headley, say intelligence agencies, had visited India nine times on his US passport (No. 097536400), issued March 10, 2006 that was valid for 10 years.
According to officials probing Headley's connections, he had an eye for detail and was capable of meticulous planning.
Headley, who changed his name from Daood Gilani in 2006, and his alleged accomplice Tahawwur Hussain Rana, a Canadian citizen of Pakistani origin, were arrested in the US last month by the Federal Bureau of Investigation (FBI).
The FBI later informed the Indian intelligence agencies that the two were plotting terror attacks on behalf of the LeT against India and the National Defence College in New Delhi and two premier educational institutions were on their hit list.
An FBI team is expected in India next week to probe the Indian links of Headley and will be joined by security agencies in Mumbai.
"The FBI investigation shared with Indian investigators reveals that Headley has played an important role in conspiring the Mumbai attack. We are probing this link," the officer said, pleading anonymity.
"The criminal complaints the FBI has so far shared expose a serious plot against overseas targets by the two working for the LeT," the official said.
Intelligence agencies were also investigating Headley's suspected links to terror outfit Indian Mujahideen, which had carried out a series of bomb attacks across the country, including in Jaipur, Delhi and Bangalore last year.
Headley and Rana have been charged by the FBI of plotting to attack a Danish newspaper whose cartoons of the Prophet Mohammed that led to violent protests by Muslims.
Headley, according to investigators, also travelled to Pakistan where he met with a militant having ties with Al Qaeda, Harakat-ul Jihadi Islami, and communicated with members of the Lashkar-e-Taiba about their plans to conduct fresh attacks in India.
Home Minister P. Chidambaram Thursday said Headley was in India before and the after the 26/11 terror carnage that left over 170 people dead in India's financial capital.
India's National Investigating Agency has already registered cases against Headley and Rana and has sought their deportation.
Headley's passport details, a xerox copy of which police got from a Delhi hotel, revealed he had come to the capital from Abu Dhabi March 6 this year - the ninth and his last visit to India. He is also suspected of having a Pakistani passport, the officials say.
According to Delhi Police, during his recent visits to the capital he stayed in two hotels of Delhi in crowded Paharganj, a popular destination for foreign backpackers.
On March 6, he stayed at Hotel Holiday International and then for the next two days at Hotel Anand, from where he checked out saying he was leaving for Rajasthan, according to hotel records.
Meanwhile, Mumbai Police have also questioned Bollywood filmmaker Mahesh Bhatt's son Rahul for his alleged friendship with Headley. Rahul, a fitness instructor, was let off after questioning as he was unaware of Headley's terror links, said sources in the Mumbai Police.
"How would you think that a white American had anything to do with terror," Mahesh Bhatt told reporters when asked about his son was questioned.
In Mumbai, Headley also met realty broker Sunny Singh to rent a flat through a former French client. However, since he could not provide proper documents, he did not help him get a flat, the property dealer said.
"I asked him for copies of his visa, passport and other identity papers, which he was not ready to provide," he said.