David Coleman Headley (born Dawood Sayed Gilani; June 30, 1960) is an American Islamist terrorist who was the mastermind behind the 2008 Mumbai attacks. With the Pakistan-based Islamist terrorist organization Lashkar-e-Taiba (LeT), Headley conducted extensive surveillance and reconnaissance missions throughout central Mumbai, providing critical information to facilitate planning and executing the attacks. Additionally, he, along with his accomplice Tahawwur Hussain Rana, was involved in an unsuccessful plot to carry out an attack in Copenhagen, targeting the Danish newspaper Jyllands-Posten. For both of these crimes, Headley was convicted of 12 counts of terrorism and sentenced to 35 years in prison.

Born in Washington D.C., as an adult Headley became involved with drugs and trafficking. He was recruited as a U.S. Drug Enforcement Administration (DEA) informant as part of his plea deal following conviction for multiple heroin-related offenses, including attempting to smuggle narcotics into the U.S. from Pakistan. After being placed on probation, he made frequent unauthorized visits to Pakistan. There he became involved in the local jihad movement through his introduction to Lashkar-e-Taiba (LeT). Under the direction of LeT representatives, Headley performed five surveillance missions in Mumbai to scout targets for the 2008 Mumbai attacks. The following year, he performed a similar mission in Copenhagen to help plot an attack against the Danish newspaper Jyllands-Posten, which had published cartoons of Muhammad. Headley was arrested in October 2009 at O'Hare International Airport in Chicago with co-conspirator Tahawwur Hussain Rana while on his way to Pakistan. On January 24, 2013, a U.S. federal court sentenced Headley to 35 years in prison for his role in Mumbai and Copenhagen.

In India, a Mumbai special court held a trial in absentia for Headley in early February 2016, via a video link from his prison cell in the United States.

Early life David Coleman Headley was born Dawood Sayed Gilani on June 30, 1960, in Washington, D.C., to a Pakistani father and an American mother. His father Sayed Salim Gilani was a well-known Pakistani diplomat and broadcaster, while his mother Alice Serrill Headley worked as a secretary at the Pakistani embassy in Washington D.C., and hailed from Bryn Mawr, Pennsylvania."Did not attend funeral of Headley's father: Gilani", The Economic Times Headley has a younger sister, Syedah, and a half-brother, Danyal. Danyal became the spokesman for Pakistani Prime Minister Yousaf Raza Gillani and served as Pakistan's press attaché in Beijing.

Shortly after Headley was born, his family left the United States and settled in Lahore, Pakistan. Headley stood out because of his light skin color and the heterochromic coloration of his eyes. Headley's mother was unable to adapt to Pakistani culture and returned to the U.S. Due to Pakistani custody rules, she was forced to leave her children with their father in Lahore. After getting a divorce, she went through four more marriages and spent time in Southeast Asia and Afghanistan.Alice Serrill Headley, born on her father's farm in Laurel, Maryland, July 29, 1939, was a daughter of L. Coleman Headley and his wife, the former Frances Ladd Kercher. She was educated at Catholic schools in the Philadelphia area, ran away from home at age 15, and married five times. After her divorce from Sayed Gilani in the mid-1960s, she wed Shahzada "Musleh" Muslehuddin (married 1966); the Pakistani movie director Aejay "AJ" Kardar (married 1969, annulled after four months, died 2002); Richard Pothier (married 1980, divorced circa 1991); and a man named Forrester (married 2006). Information on her birth, parents, marriages, and family is posted at ancestry.com, where it was accessed on October 16, 2010.

Headley was raised in a political environment steeped in Pakistani nationalism and Islamic conservatism, both of which were amplified by Pakistani tensions with India. During the Indo-Pakistani War of 1971, bombs hit Headley's elementary school in Karachi and killed two people. Headley went on to attend the elite Cadet College Hasan Abdal, a boys' international military prep school; while there, he befriended co-conspirator Tahawwur Hussain Rana.

In 1977, at the age of seventeen Headley left Pakistan following a difficult relationship with his Pakistani stepmother, and moved in with his biological mother in Philadelphia, where he helped her manage pubs such as the Khyber Pass Pub and the adjacent Miss Headley's Wine Bar. Employees at the pub nicknamed him "The Prince." Headley enrolled at Valley Forge Military Academy but dropped out after one semester. He was a student at the Community College of Philadelphia but dropped out without a degree in the 1990s. In 1985, he married a Pennsylvania State University student, but they divorced two years later due his ideological hostility.Headley's ex-wife told reporters, "when he would go to Pakistan he would get all riled up again" and use words like "infidels" and "when he would see an Indian person in the street, he used to spit, spit in the street". He eventually moved to New York City and opened a video rental business in Manhattan.

Drug Convictions and DEA Deal During his frequent trips to Pakistan, Headley associated himself with heroin users and started using the drug himself. He became involved in Pakistani drug trafficking. When he was twenty-four, Headley smuggled half a kilogram of heroin out of Pakistani tribal areas and used Tahawwur Hussain Rana, a Pakistani army doctor who Headley knew from military school, as an unwitting shield. Several days later, police in Lahore arrested Headley for drug possession, but he was released. Rana continued to be used by Headley over the course of his career as a drug trafficker; in the late 1990s, after Rana had emigrated to the U.S., Headley used Rana's legitimate immigration consulting company in Chicago to smuggle drugs.

In 1988, while he was traveling to Philadelphia from Pakistan, Headley was arrested by police in Frankfurt, West Germany after two kilos of heroin were found hidden in a false bottom in his suitcase. Headley quickly made a plea deal when his case was handed over to the U.S. Drug Enforcement Administration, agreeing to surrender his partners in Philadelphia in exchange for a lighter sentence. Headley's cooperation earned him four years in prison while his two associates were sentenced to eight and ten years. At his sentencing hearing, the judge made the following statement: "It's up to you, Mr. [Headley], to do what you can with the rest of your life. You are still a young man. You can either take advantage of this opportunity. Your mother, your lawyer, people said some nice things about you, but what you did, not only to yourself, but to perhaps thousands, hundreds of victims, heroin users in this country is a terrible thing."Interactive: David Coleman Headley's Web of Betrayal, PBS. Retrieved July 26, 2013

Headley managed to overcome his addiction to heroin, but was still involved in the drug trade. In early 1997, Headley was arrested with another man in a DEA sting operation when he tried to smuggle heroin into the country from Pakistan. Headley quickly offered his services as a confidential informant to the DEA. In January 1998, the agency sent him to Pakistan to dispel suspicions amongst his partners about his prior absence, and to gain intelligence on the country's heroin trafficking networks. According to the DEA, Headley's participation led to five arrests and the seizure of 2½ kilos of heroin.Headley 1997 sentencing letter, ProPublica, January 24, 2013 The DEA has insisted that Headley's 1998 trip to Pakistan was the only one paid for by the agency.

While the DEA seemingly made great gains from Headley's intelligence, there is ample evidence that Headley abused his status as an informant. He allegedly tried to set up heroin dealers with jailhouse phone calls that were not monitored by DEA agents. A mentally impaired Pakistani immigrant, Ikram Haq, was found to have been tricked into making a drug deal by Headley, and was subsequently acquitted on the grounds of entrapment when brought to trial. Despite this result, Headley was released from prison and put on probation for his contribution to the case. One anonymous former associate of Headley later suggested that he was exploiting his rapport with the DEA, saying, "The DEA agents liked him. He would brag about it. He was manipulating them. He said he had them in his pocket."

Involvement in terrorism In exchange for information about Pakistani drug contacts, Headley received a considerably lighter sentence than his co-defendant from the 1997 arrest: fifteen months in jail and five years of supervised release. In November 1998, he was delivered to the low-security Federal Correctional Institution, Fort Dix. There, he became an increasingly devout Muslim. In July 1999, only months into Headley's sentence, his attorney, Howard Leader, requested permission for him to be given a supervised early release from prison so he could travel to Pakistan to be wed in an arranged marriage. Judge Carol Amon granted the unusual request. Headley married a Pakistani woman named Shazia and fathered two children with her.

While visiting Lahore, Headley was introduced to Lashkar-e-Taiba (LeT), a terrorist organization. Headley made further trips to Pakistan without the knowledge of U.S. authorities, immersing himself in LeT ideology. He befriended LeT's spiritual leader, Hafiz Muhammad Saeed, and committed himself to the group's struggle against India, which was supported by the Directorate for Pakistan's Inter-Services Intelligence (ISI)

At the same time this was happening, Headley resumed work as a DEA informant in New York City and participated in an undercover operation that reportedly led to the seizure of one kilo of heroin. Despite working for a U.S. government agency, Headley actively raised money and recruited new members for LeT, a group that swore allegiance with Al-Qaeda. Headley would later testify that he discussed his views regarding Kashmir—the focus of LeT's terrorist activities—with his DEA handlers. The DEA has insisted that it was unaware of Headley's political and religious radicalization.

Post-9/11 activities A day after the attacks on September 11, 2001, Headley's DEA handlers tasked him with collecting counter-intelligence on terrorists through his sources in the drug trade. However, a New York City bartender named Terry O'Donnell reported Headley to an FBI task force after Headley's ex-girlfriend told him that Headley had praised the 9/11 hijackers and "got off on watching the news over and over again" in the weeks following the attacks. Under questioning by two Defense Department agents, in the presence of his DEA handlers, Headley denied the accusations and cited his work for the DEA as proof of his loyalty to the U.S. Headley was cleared, and the DEA did not write a report on his interrogation.The American Behind India's 9/11—And How U.S. Botched Chances to Stop Him, ProPublica, January 24, 2013.