The FBI's investigation into young Minnesotans leaving for Syria to join or fight for radical groups has put Muslim leaders on alert for terrorist recruiters.

Left unsaid: Who is a terrorist recruiter?

FBI officials won't share everything they know about who they are looking for. That is standard procedure, but it's created a vacuum in which suspicions and speculation flourish.

• Called to Fight: Recruiting Minnesotans to fight abroad

Some local Muslims say they're struggling to understand who might be dangerous and who's simply opinionated. They warn of a hyper-vigilant environment where even innocent people are creating unease in their community.

"The problem is that people don't know what to report," said Lori Saroya, executive director of the Minnesota chapter of the Council on American-Islamic Relations. Her office has fielded calls from Muslims worried about possible extremists or even government informants in their midst.

"We've had cases where people are reporting white converts who are coming to their mosques," she said. "Any new person who comes into the mosque, anyone who's even a little bit suspicious, they report."

Since first learning in 2007 that young Twin Cities men were traveling to Somalia to join the terror group al-Shabab, the FBI and the U.S. Attorney's Office in Minneapolis have deepened their outreach to the local Muslim community, particularly Somali-Americans.

U.S. Secretary of Homeland Security Jeh Johnson delivered a message of cooperation last week in Minneapolis. "If you see somebody who may be headed in the direction of violence, who is disaffected, who's angry in some way," he said, "help us to help you."

Johnson also repeated what's become a slogan for his department: If you see something, say something. But that can be a hard sell, especially when many Muslims remain wary of law enforcement.

A federal grand jury in Minneapolis has been investigating a possible recruitment pipeline to Syria. But the proceedings are secret, and authorities haven't said who they're focusing on. No one from Minnesota has been charged in the case.

Their silence, which is the standard for open investigations, may actually create more anxiety, for Muslims and non-Muslims alike.

"We don't know what's going on in the community, and it's frightening for all of us," said Afsheen John Radsan, a former CIA attorney who teaches at William Mitchell College of Law.

Concerns about terrorist recruitment within the United States, as they are playing out in the Twin Cities, can test a community's values, Radsan added.

"We want to be safe. We want to protect democracy," he said. "We want people to freely pursue their religions, but we don't want mosques or other religious places to become centers of terrorism recruitment. So we're trying to find the right balance of protecting everyone and being open-minded — but not being naive about what could be going on right here."

On the lookout

Ever since al-Shabab recruited within a large Minneapolis mosque several years ago, Muslim leaders have been on the lookout for possible extremists.

In 2011, that same mosque, the Abubakar As-Saddique Islamic Center, kicked out a few young men who challenged leaders and appeared to sympathize with al-Shabab. The last straw was when one of the men punched the mosque director in the face.

But extremist thought doesn't necessarily mean someone will turn violent, and that's the dilemma that many Muslims face. They worry that calling law enforcement on someone who might be troubled, but not necessarily dangerous, will subject that person to years of scrutiny or even entrapment.

"The FBI is not interested in the policing of speech, or expression, or ideas," said Kyle Loven, a spokesman for the FBI division in Minneapolis.

"But if there are individuals who are expressing jihadist ideas, coupled with changes in behavior, changes in mood, and if there are other factors, what we would ask is people come forward and at least bring it to our attention so the FBI can make the determination if a potential threat exists," Loven said. "We don't want concerned individuals out there guessing."

Amir Meshal AP

In Eden Prairie, leaders of Masjid Al-Tawba never thought they would find themselves in the position of ousting someone from their flock. But a few months ago, Al-Tawba mosque leaders grew worried after learning a man named Amir Meshal had begun worshiping at Friday prayers.

The 31-year-old New Jersey native had been in the news after another local mosque, Al-Farooq, filed a no-trespass order against him. According to a July incident report with Bloomington police, officials at Al-Farooq had "concerns about Meshal interacting with our youth."

Two young people who worshiped at Al-Farooq traveled to Syria this year, according to a mosque attorney. It's not clear if Meshal knew them. An 18-year-old man who also attended Al-Farooq attempted to leave and was stopped by authorities at Minneapolis-St. Paul International Airport.

Officials with Al-Farooq declined to comment for this story.

Mosque leaders in Eden Prairie said they wrestled with what to do with Meshal. Al-Tawba board member Ali Jaafar said they had no proof that Meshal was trying to radicalize anyone, so they didn't feel like they could simply expel him.

Ali Jaafar is a board member of the Masjid Al-Tawba Islamic Cultural Community Center. He said allowing radical views inside the mosque would destroy his organization's credibility. Laura Yuen / MPR News

"What I agonized with is telling someone they cannot come and pray, and then come to find out I was wrong. That would be a grave, heavy burden to me," Jaafar said. "You're denying someone the right to worship God. Who am I to do that?"

Jaafar said Meshal made the decision easier for mosque officials after a worshiper told them Meshal voiced his disagreement with an imam's call to distance Islam from radical groups, including Islamic State, or ISIS. The imam criticized the idea that anyone might come to rule a so-called Islamic state through oppression and murder.

"What I agonized with is telling someone they cannot come and pray, and then come to find out I was wrong. That would be a grave, heavy burden to me."

Mosque officials called Eden Prairie police to ask them what legal actions they could take. Following an officer's advice, mosque leaders asked Meshal to leave the next time he appeared at the mosque. He hasn't been seen there since.

Al-Tawba's imam, Jamel Ben Ameur, said he felt his center had to protect its youth from what he considers an extreme interpretation of Islam.

"We're not overreacting," Ben Ameur said. "What's being reported in the news and what we're seeing is something to be scared of."

A climate of 'fear and mistrust'?

Amir Meshal's attorney, Hina Shamsi, said her client has done nothing wrong and is trying to live his life in peace. Meshal has received no indication from federal prosecutors that he's a target of the investigation, she said.

The Twin Cities mosques are responding only to unfounded rumors, Shamsi said.

"Fear and mistrust [are] roiling American Muslim communities, with potentially very negative consequences for innocent people."

"What seems to be happening reflects what we are seeing in different parts of the country where fear and mistrust is roiling American Muslim communities, with potentially very negative consequences for innocent people," she said.

But it wasn't just Meshal's comments that raised the mosque officials' concerns. Meshal's relationship with the FBI has been well-documented in his lawsuits against the U.S. government, and mosque leaders were aware of that history through news reports.

Meshal's court filings show he traveled to Somalia in late 2006. Meshal, a U.S. citizen, said he went to study the Quran. After fighting broke out in Somalia, he was among the throngs of people trying to flee the country.

At the time, the U.S. government was concerned that Somalia was a refuge for al-Qaida members leaving Afghanistan. In early 2007, Kenyan troops detained Meshal near the border.

He was shuffled among secret jails in Kenya, Somalia and Ethiopia, where FBI agents interrogated Meshal and falsely accused him of receiving weapons training from al-Qaida, according to the lawsuit.

The ACLU, which filed the lawsuit on his behalf, alleged the U.S. government violated his constitutional rights by threatening him with torture and denying him access to an attorney.

Four months after his capture, Meshal was released to his home in his native New Jersey, 80 pounds lighter, according to his lawsuit. He was never charged with a crime.

In a second lawsuit filed by the ACLU, Meshal claimed that federal authorities barred him from flying. He also alleged the FBI offered to take him off the no-fly list if he became an informant.

His attorney, the ACLU's Shamsi, said her client is not working for the government. The FBI has pressured Meshal more than once, but he's not interested, Shamsi said.

"This is a man who was arrested, secretly imprisoned in inhumane conditions, and harshly interrogated by the FBI. He has sued to vindicate his rights against unlawful government conduct," Shamsi said. "I leave that to your listeners to decide whether someone like that is, or is not, likely to be an informant. He is not."

According to court documents, Meshal works as a bus driver. He lives in a Bloomington apartment complex with his wife and newborn baby. Meshal declined to comment for this story.

The FBI and U.S. Attorney Andy Luger also declined to comment on Meshal.

The Meshal case aside, many Twin Cities Muslims assume the FBI is using informants to gather information at the mosques.

That assumption is compounded by the reticence of law enforcement officials, who won't comment on investigative tactics.

Luger said investigators are aggressively focusing on a small number of individuals in hopes of stopping the flow of young Minnesotans to a battlefield in the Middle East. At least two people with Twin Cities ties are believed to have been killed fighting for ISIS.

"Everybody who we've stopped from traveling to Syria," he said, "represents a life we've saved."