The FBI alleges Mr Headley attended militant training camps in Pakistan
A man in the US has pleaded not guilty to a new set of charges in connection with the deadly 2008 Mumbai attacks, some of which carry the death penalty.
David Coleman Headley, a Pakistani-American, is accused of identifying targets in Mumbai before the assaults.
He already stands accused of plotting to attack a Danish newspaper which published inflammatory cartoons of the Prophet Mohammed in 2005.
US prosecutors said Mr Headley was co-operating with both investigations.
Born in 1960 in the US to a Pakistani father and an American mother
Spent much of his childhood in Pakistan
Attended a military boarding school in Islamabad
Dropped out of school at 17
Joined his mother in the US after she divorced his father
Changed his name to David Headley in 2006
Made five extended trips to Mumbai between 2006 and 2008
FBI says he took pictures and made videotapes of various targets, including those attacked in 2008
Arrested in Chicago on 3 October 2009 as he was about to travel to Pakistan
The Mumbai attacks in November 2008 left 174 people dead, including nine gunmen.
"He did enter a plea of not guilty on the charges," Mr Headley's lawyer John Theis was quoted as telling reporters by the AFP news agency.
"We will be reviewing the charges and we don't have any information at this time as to the outcome of the case," he said.
Mr Theis said that the defence team was "in discussions with the government" about the charges.
Earlier this week Tahawwur Rana, a Chicago businessman and a friend of Mr Headley, pleaded not guilty to charges relating to the Mumbai attacks.
Mr Rana is alleged to have helped Mr Headley plot the attacks. He was arrested together with Mr Headley last October.
The Chicago branch of the FBI says David Headley attended Lashkar-e-Taiba training camps in Pakistan in 2002 and 2003, where he conspired to plan and carry out attacks in both India and Denmark.
Prosecutors say Mr Headley changed his name from Daood Gilani in 2006 after he was told by members of Lashkar-e-Taiba that he would be travelling to India to carry out surveillance duties for the group.
The FBI said his aim was to present himself as an American citizen without any links to Pakistan or Islam.
After repeated trips to India in 2006 and 2008, investigators said, he returned to Pakistan where he would provide his alleged co-conspirators with photographs, videos and descriptions of locations he is accused of having staked out.
Last December, Mr Headley pleaded not guilty to a separate set of charges relating to the Mumbai attacks.