Mohammed Hamzah Khan knew he was being watched. The 19-year-old college student passed through security at O’Hare with his 17-year-old sister and 16-year-old brother on the afternoon of October 4, 2014. But even then, he expected to be stopped by federal agents who he thought had been spying on him. He was right.

But Khan’s siblings told different stories, according to the federal officers: his sister said they intended to stay with a friend, while his brother said they were going to visit their cousins.

Early the next morning—after Khan was questioned for nearly 12 hours without an attorney present—federal officials formally charged him, though they elected to release his underage siblings to their parents. Within hours the case generated international news coverage that wondered how a polite suburban teenager with college-educated parents could have been lured to a brutal terrorist group.

While it’s critical to stop potential extremists before they’re drawn to carrying out violence, Mockaitis is in a camp calling to respond where possible with “restorative justice” such as education and counseling—much the way that former cult members are often led through a “deprogramming” process. “We did the right thing to arrest him,” he says of Khan. “The question is what we do now.”

Still, the idea of the caliphate appeals to some discontented young men and women, and ISIS has made outreach a priority. “It’s something that started with al-Qaeda, and ISIS has upped the game and has become very good at online propaganda, social media campaigns, and recruitment,” says Ted Reynolds, a senior research fellow in terrorism studies at the University of Central Florida. When someone expresses interest in heading to ISIS territory, “ISIS facilitators then become their travel agents.”

At the same time, extremists aren’t the only threat perceived by the Muslim community. “I know quite a few situations in which informants have approached people at mosques who are slow and asked them to keep in touch,” Mozaffar says. “I have to say that if you come across someone at the mosque promoting violence, they probably work for the feds.”

Federal authorities have brought terrorism charges against several Chicago-area men in recent years. Below are the criminal complaints against three defendants still in court and the plea agreement of Sami Hassoun, who is serving a 23-year sentence on attempted bombing charges.

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Plea agreement of Sami Hassoun

Complaint brought against Adel Daoud

Complaint brought against Mohammed Hamzah Khan

Complaint brought against Abdella Ahmad Tounisi