A New York man was sentenced to 15 years in prison for his “extensive efforts” in financially supporting al Qaeda and providing assistance in surveillance of the New York Stock Exchange for nearly three years for a potential attack by the militant group, the FBI announced Tuesday.

Wesam El-Hanafi, 39, was arrested in the United Arab Emirates in April 2010, and then transferred to the United States. In June 2012, El-Hanafi pleaded guilty of providing and conspiring to provide material support and resources to al Qaeda, according to the FBI.

“Wesam El-Hanafi was deeply involved in supporting Al Qaeda both financially and by facilitating surveillance of a New York landmark to bring an attack to our homeland in our city,” Preet Bharara, U.S. attorney for the Southern District of New York, said in a statement. “Today’s sentence is a fitting punishment for these crimes and we will continue, with our law enforcement partners, to pursue punishment for those who provide and conspire to provide material support for terrorists.”

El-Hanafi, who formerly resided in Brooklyn, supported al Qaeda in a variety of ways from 2007 through late 2009. In 2007, El-Hanafi and his associate Sabirhan Hasanoff, a dual U.S.-Australian citizen, developed contacts with individuals, who were believed to be affiliated with al Qaeda, and provided them financial support, the FBI said, citing court filings.

El-Hanafi and Hasanoff together sent about $67,000 to terrorist operatives overseas, while they collected some of the money from a third person who also resided in the U.S., according to the FBI.

“He was living the American dream,” Reuters quoted Assistant U.S. Attorney John Cronan as saying to U.S. District Judge Kimba Wood. “And then he turned his back on America and aligned himself with our greatest enemy.”

In February 2008, El-Hanafi went to Yemen, where he delivered money and other items, including a laptop, to the terrorists. El-Hanafi, who worked as an information technology employee for Lehman Brothers at the bank’s Dubai offices until his arrest, used his expertise to teach the terrorists in Yemen secret Internet communications techniques to avoid detection while communicating online.

In addition, El-Hanafi and Hasanoff both sent other items, including remote-controlled devices, which could be used to detonate explosives. Hasanoff, a former accountant for KPMG and PricewaterhouseCoopers, also pleaded guilty in June 2012 and was sentenced to 18 years in prison, Reuters reported.

El-Hanafi’s sentence comes at a time when the U.S. and the U.K. have become increasingly concerned about home-grown terrorists who are inspired by extremist groups to launch attacks in Western countries.

Last week, the FBI arrested an Ohio man for allegedly planning to bomb the U.S. Capitol. The man was also accused of vocalizing his support for “jihad” on Twitter, and for allegedly posting statements, videos and other content in support of the Islamic State group.