Surveillance trips

After his trips to India, Headley travelled to Pakistan to turn over the results of his surveillance and, in early 2008, he took boat trips into the Mumbai harbour, according to court documents released by the US justice department.

In November 2008, 10 attackers launched their assault on various targets in Mumbai, including several where Headley had conducted surveillance, according to the documents. The attackers had arrived in Mumbai by boat.

"This investigation remains active and ongoing," said Patrick Fitzgerald, the US attorney for the Northern District of Illinois, where the charges were filed.

"The team of prosecutors and agents will continue to seek charges against the other persons responsible for these attacks."

The charges against Headley include aiding and abetting the murder of six Americans who died in the Mumbai attacks.

A lawyer for Headley declined to comment.