The Home Ministry is examining the one-page report sent by the US yesterday on the findings of a "full review" on the inputs it had received on the Pakistani-American Lashkar-e-Tayiba terrorist before or after 26/11 terror attacks.
Officials said that had there been any indication that Headley changed his name from Dawood Gilani and that he was a Pakistani-American, it would have definitely alerted Indian immigration officials during his multiple visits here.
"But there was no indication of it in his passport. Moreover, someone must have helped him change his name," an official said. In its one-page report, the US informed India that intelligence inputs it had about the Mumbai terror plotter was not enough to sufficiently establish his role in planning the 26/11 terrorist attack.
The US security agencies received only some general information relating to Headley and his activities but nothing specific which could connect with Mumbai terror attack in 2008, it said.
US President Barack Obama had yesterday also shared with Prime Minister Manmohan Singh results of the ongoing probe into why US intelligence agencies failed to connect the LeT terrorist to the Mumbai attacks.
India is also planning to send Letters Rogatory to the United States seeking copies of the complaints made by 26/11 plotter Headley's two wives about his training with Pakistani militants for a "special mission" against India.
Fifty-year-old Headley, currently in the custody of America, had pleaded guilty to plotting the Mumbai attacks that left 166 people dead under a deal with the US investigators that will allow him to escape death penalty.
According to a report from Washington, a review being conducted for the Director of National Intelligence James Clapper has found that since 2001 a number of leads emerged about Headley, that if taken cohesively could have busted the LeT plot to attack Mumbai in 2008.
Union Home Secretary G K Pillai said last month that the Home Ministry was "disappointed" that the US did not provide specific information about Headley, who had plotted the Mumbai attacks, even though he travelled here freely after the terror strike.
The US media also reported that Headley was sent to Pakistan by US authorities to work for them as an informant after 9/11 despite a warning that he sympathises with extremist groups.