Even the federal prosecutors who charged a 25-year-old Minnesota man with aiding terrorists admit he didn't know he was signing up for jihad when he accepted a free trip to Somalia.

Abdifatah Yusuf Isse told investigators he grabbed the free ticket to see his grandmother in his homeland. But after arriving, he joined up with Al Qaeda-allied Somali militants. Though he later escaped and returned to the U.S., he was arrested in February at Seattle's airport.

Isse's story echoes claims made by relatives of some of the other Somali men who have disappeared from Minneapolis over the last 18 months, a group believed to be as large as 20. Three have died in Somalia. Infants or toddlers when their families fled Somalia's civil war, most of the men were preoccupied by adulthood with American concerns: school, sports and girls.

But once they were in Somalia, Isse and the others trained with al-Shabab, which the U.S. State Department calls a terrorist organization. Their disappearances prompted a federal investigation that's raised fears the American passport holders could pose a threat to the U.S.

Some, like Isse, appear to have stumbled from American life into circumstances they didn't fully understand. But others — including one man who blew himself up in a suicide attack last year may not have been so clueless when they traveled to the lawless East African country.

Their families, though, are convinced their sons were targeted by recruiters preying on vulnerable victims who didn't understand their homeland.

"These guys were very naive," said Abdirizak Bihi, a Minneapolis Somali activist and uncle to one of the men who was killed, Burhan Hassan. "They didn't have any clue about Somalia and the Somali culture. They were walking into a civil war and decades of clan warfare, and they didn't have any clue what Somalia is."

Most led typical American lives. They attended high schools and wore Western clothes. Some had jobs and played basketball at a community center.

"Burhan showed to me a lot more interest in the NBA than in anything that was ever going on in Somalia," said Bihi.

Another one of the men killed, Jamal Bana, took engineering classes at a community college. His mother says her son "had no clue" about what would happen in Somalia.

Family members say they were good kids, but a few had run-ins with police. Some may have struggled to find their own identity, with knowledge of Somalia gleaned only from the Internet, books and stories from older relatives.

Minnesota's state demographer estimates more than half of the state's roughly 32,000 Somali residents live in poverty, and many of the men came from poor families.

Several also were raised by single mothers in a community that highly values male leadership. Many turned to their local mosque, a place where Muslim men can find mentors. Court documents have indicated some of the recruiting may have happened at a mosque.

One young Somali man being questioned by a federal grand jury was approached by another older Somali man, who is on the list of those who have disappeared, said the younger man's attorney, Stephen Smith.

Smith believes the older man approached his client because "maybe because he thought he was impressionable."

"I think, frankly, he was probably exploiting his position of influence and trust," Smith said.

Jeffrey Addicott, director of the Center for Terrorism Law at St. Mary's University in San Antonio, Texas said impressionable youth commonly look toward religion to fill a perceived void in the lives. But terrorist recruiters are known to prey on vulnerable men at mosques, he said.

"They cloak themselves in legitimate mosques and once they get in there, they identify people who might be responsive to this new ideology of Islam," he said.

One of the men, Shirwa Ahmed, detonated himself as part of a wave of suicide attacks that killed about 20 people in Somalia in late October. Friends say the young man who liked movies and basketball grew more religious in the months before he left for . He is believed to be the first-ever American homicide bomber, the FBI says.

So far, the federal investigation has netted Isse and one other suspect. Isse has pleaded guilty to providing support to terrorists and is cooperating with investigators who are trying to piece together the murky web connecting the disenfranchised Somali youth to al-Shabab, which means "youth" in Arabic. Another Minnesota Somali man, Salah Osman Ahmed is set to go on trial in October on terror-related charges.

Prosecutors say in Somalia, Isse and others lived in al-Shabab houses, had weapons training and helped build a training camp. The group, which opposes Somalia's embattled government, denies al-Qaida ties but experts say hundreds of foreign fighters are helping the Islamist militants.

Though relatives and friends in Minnesota hope the federal investigation will stifle the recruitment, they worry it may be too late to help those still missing.

"There is a lack of understanding from these young men about life and death and its importance," said Warsame Hassan, the brother-in-law of Burhan Hassan.