An American-Syrian citizen and college student from Boston is suspected of being behind the Islamic State, formerly ISIS, militant group's social media propaganda, ABC reported, citing a n anonymous senior law enforcement official.

The student, Ahmad Abousamra, was born in France in 1981 but grew up in Boston, and has been on the run from the FBI for years.

He was first questioned in 2006 by the FBI's Joint Terrorism Task Force, and then fled to Syria.

The FBI questioned him about activities related to the al Qaeda in Iraq (AQI) group, which eventually became ISIS, where he and two others were linked to similar media propaganda for the group.

After fleeing, he was charged with terrorism-related offenses in 2009, and added to the FBI Most Wanted Terrorists list in 2013, ABC reported.

Abousamra was linked to an unidentified individual and Tarek Mehanna for working as a "media wing," but Mehanna was the only one arrested and convicted.

The concern now is that Abousamra is working a similar job with IS.

"There continues to be a worldwide search for Abousamra and he will be pursued until he is found," FBI Assistant Special Agent in Charge Kieran Ramsey told ABC.

Abousamra's early life was privileged, according to ABC.

His father was a prominent endocrinologist at Massachusetts General Hospital, attended a prviate Catholic school until senior year, was on the Dean's List at Northeastern University, and obtained a degree in computer technology.

He was previously employed at a telecommunications company before leaving to Iraq in 2004 where he allegedly was going to fight Americans, ABC reported.

"ISIS understands very well that in order for an act of terrorism to be effective, it needs to actually terrorize people," Peter Neumann, Director of the International Centre for the Study of Radicalisation (ICSR), told ABC. "The act of communication that follows the act of violence is almost as important as the act of violence itself."

There is a $50,000 reward for information leading to Abousamra's capture.