Young Somali jihadists ‘radicalized’ while in US, federal investigators say

They had fled Somalia as small boys, escaping a catastrophic civil war. They came of age as refugees in Minneapolis, becoming naturalized US citizens and embracing basketball and the prom, hip-hop, and the Mall of America. By the time they reached college, their dreams seemed within grasp: one planned to become a doctor; another, an entrepreneur.

But last year, in a study room on the first floor of Carlson, the men turned their energies to a different enterprise.

“Why are we sitting around in America, doing nothing for our people?’’ one of the men, Mohamoud Hassan, a skinny, 23-year-old engineering major, pressed his friends.

In November, Hassan and two other students dropped out of college and left for Somalia, the homeland they barely knew. Word soon spread that they had joined the Shabaab, a militant Islamist group aligned with Al Qaeda that is fighting to overthrow the fragile Somali government.

The students are among more than 20 young Americans who are the focus of what may be the most significant domestic terrorism investigation since 9/11.

One of the men, Shirwa Ahmed, blew himself up in Somalia in October, becoming the first known American suicide bomber.

The director of the Federal Bureau of Investigation, Robert S. Mueller III, has said Ahmed was “radicalized in his hometown in Minnesota.’’

An examination by The New York Times, based on interviews with close friends and relatives of the men, law enforcement officials, and lawyers, as well as access to live phone calls and Facebook messages between the men and their friends in the United States, reveals how a far-flung jihadist movement found a foothold in America’s heartland.

The men appear to have been motivated by a complex mix of politics and faith, and their communications show how some are trying to recruit other young Americans to their cause.

The case represents the largest group of US citizens suspected of joining an extremist movement affiliated with Al Qaeda. Although friends say the men have never thought of carrying out attacks in the United States, FBI officials worry that with their training, ideology, and US passports, there is a real danger that they could.

Most of the men are former Somali refugees who left the Twin Cities of Minneapolis and St. Paul in two waves, starting in late 2007. While religious devotion may have predisposed them to sympathize with the Islamist cause in Somalia, it took a major geopolitical event - the Ethiopian invasion of Somalia in 2006 - to spur them to join what they saw as a legitimate resistance movement, said friends of the men.

The case has forced federal agents and terrorism analysts to rethink some of their most basic assumptions about the vulnerability of Muslim immigrants in the United States to the lure of militant Islam. For years, it seemed that “homegrown’’ terrorism was largely a problem in European countries like Britain and France, where Muslim immigrants had failed to prosper economically or integrate culturally. By contrast, experts believed that the successful assimilation of foreign-born Muslims in the United States had largely immunized them from the appeal of radical ideologies.