MINNEAPOLIS — Tall and lean, with a wispy mustache and shy smile, 17-year-old Burhan Hassan chalked up A's last fall as a senior at Roosevelt High School, vowing to become a doctor or lawyer.
After school and on weekends, he studied Islam at the nearby Abubakar As-Saddique mosque. He joined its youth group.
"He wanted to go to Harvard," said his uncle Osman Ahmed. "That was his dream."
Instead Hassan has gone to Somalia, the anarchic East African nation that his family fled when he was a toddler. On election day, Hassan and five other youths slipped away from their homes here, and anguished family members now say they may have joined a Taliban-style Islamic militia that U.S. authorities call a terrorist organization.
The youths, who have U.S. passports, followed a well-trod trail from Minneapolis to Mogadishu. Another group took off in August. The FBI believes that over the last two years, 12 to 20 Minnesotans have gone to Somalia.
As a result, a joint terrorism task force led by the FBI is scrambling to determine if extremist Islamic groups are seeking recruits here in the nation's largest Somali community -- as well as in San Diego, Seattle, Boston and other cities.
"We're aware that these guys have traveled from Minneapolis and other parts of the country," said E.K. Wilson, the FBI spokesman here. "Our concern obviously is they've been recruited somehow to fight or to train as terrorists."
Topping their concern is the case of Shirwa Ahmed, a 27-year-old former Minneapolis resident who went to Somalia in 2007 -- and who may be what Wilson called "the first occasion of a U.S. citizen suicide bomber."
Officials believe the naturalized American was on a terrorist team that detonated five car bombs in two northern Somali cities on Oct. 29, killing at least 30 people, including U.N. aid workers.
Ahmed phoned his sister in Minneapolis a day before the bombings to say he would not see her again, according to a family friend. "She thought he was sick," the friend said. The next day, someone else called from Somalia to say he had "gone to paradise" as a martyr for Islam.
The FBI brought back bone fragments and other remains found in Bosaso, one of the blast sites, Wilson said. DNA tests established Ahmed's identity.
He was buried in a Muslim funeral in Burnsville, south of Minneapolis, on Dec. 3.
Ahmed had not been on the FBI's radar before the bombings. And his death raised fears that someone trained in Somalia might import terrorist tactics to America.
"There is always a concern about spillover, bleed-out, call it what you will," said a U.S. official tracking the case who requested anonymity when discussing U.S. intelligence matters. "Especially if they were to return on a U.S. passport."
In late November, Homeland Security officials put the imam of the Abubakar As-Saddique mosque and the coordinator of its youth group on a no-fly list. They were barred at Minneapolis-St. Paul International Airport from leaving on a pilgrimage to Mecca.
The imam, Abdirahman Ahmed, did not respond to interview requests. In a posting on its website, the mosque said it "unequivocally condemns" suicide bombings and other terrorist acts. It blamed the travel ban on "false, unsubstantiated rumors."
The leader of another mosque under scrutiny, the Darul Da'wah center in St. Paul, Minn., denied rumors in the Somali community that the alleged suicide bomber and several other missing men were among his followers.
"Nobody who is part of my mosque left for Somalia except one man who went for his health," the imam, Hassan A. Mohamud, insisted in an interview last week. "He left for depression, stress that he was feeling, and he will be back in three months."
It might seem odd to seek a restorative cure in a country that has been mired in war for 18 years and now is known for its pirates. But many Somalis in Minneapolis retain strong political and social ties to the intrigues and battles in their homeland.
"They each support a particular warlord back in Somalia," Omar Jamal, head of the Somali Justice Advocacy Center, explained as he puffed on a huge hookah at the crowded Pyramids Cafe and Shisha Lounge.
Somali refugees began flocking to America in the early 1990s when their homeland erupted in famine and civil war -- a chaotic bloodletting portrayed in Hollywood's "Black Hawk Down."
Like Hmong refugees before them, many Somalis moved to Minnesota for good schools, community aid and unskilled jobs in meat-processing plants and factories. A thriving Somali community, estimated at 60,000, has taken root in the state.
The largest group lives in and around a bleak cluster of high-rise apartments beside a busy highway in eastern Minneapolis, an area known as Little Mogadishu.
Women in thick shawls scurry down the icy streets as men in skullcaps pray in storefront mosques and cluster at a local Starbucks. Jobs are scarce and school dropout rates are high. According to police, gangs with names like Somali Mafia and Murda Squad killed seven people last year.