David Coleman Headley, formerly known as Daood Sayed Gilani, (born June 30, 1960) is a Chicago-based Pakistani American, who conspired with Lashkar-e-Taiba and, he claims, Pakistani military officers to launch the 2008 Mumbai attacks and other terrorist activity. He changed his Islamic name to a Christian name to hide his Pakistani-Muslim identity to make travel to India easier.
Between 2002 and 2005, Headley made several trips to Pakistan for terror training, and was in fact working as a Drug Enforcement Administration informant at the same time. Between 2006 and 2008, he did five spying missions in Mumbai scouting targets for the 2008 Mumbai attacks on behalf of Lashkar-e-Taiba and Pakistani ex-military officers. The attacks killed 168 people. In 2009, Headley traveled to Britain to help plan an attack against a Danish newspaper that had published cartoons of the prophet Muhammad. He was arrested in October 2009 on his way to Pakistan.
Since his arrest and guilty plea, Headley has been cooperating with U.S. and Indian authorities, and has yielded much information about his associates.