David Headley, a Chicago-based businessman, was arrested on October 3. A US citizen, he changed his name from Daood Gilani in 2006.
 
He went under the scanner of the investigating agency, when he along with Tahawwur Hussain Rana, were charged with conspiracy to support or commit attacks against a Danish newspaper that published controversial cartoons of the Prophet Mohammed four years ago. Headley suggested killing the editor, Flemming Rose, and the cartoonist, Kurt Westergaard. He was also in contact with Ilyas Kashmiri, a high-ranking operative in a militant group associated with al Qaida.

Headley traveled to Pakistan's Federally Administered Tribal Area to meet Kashmiri and the third alleged conspirator, identified only as Individual A, after the first trip to Denmark.
 
Headley was on the way to Pakistan again when he was arrested on October 3 at Chicago's O'Hare International Airport.