A judge Wednesday ordered Sami Hassoun held until trial.
The FBI used a confidential informant to help make their case.
Sources say that in the Chicago-area alone the FBI maintains a network of more than 1,000 people who the bureau terms "confidential human sources."
They are informants. Many are paid. Others are offered help on immigration issues or their own criminal cases.
On Wednesday, Sami Hassoun's attorney, Myron Auerbach indicated that he will argue it was the informant who turned idle talk into an actual threat.
"My client is a very troubled young man," said Auerbach.
Sami Hassoun's attorney says his client is unfocused, undisciplined and may very well have been manipulated by a person whom he thought was a friend but turned out to be working for the FBI.
"He wanted to make his confidential source happy, and he was given certain ideas and he ran with it," said Auerbach.
"The confidential human source is the true hero here," said FBI Special Agent in Charge Robert Grant Monday. "Without his cooperation - without his ability to bring in this kind of a threat - we may not have known about it."
The FBI's counter-terrorism team in Chicago asked an unnamed informant, someone who has been previously been paid by the bureau, to befriend Sami Hassoun in his Albany Park neighborhood.
It was that informant who is said to have secretly recorded Hassoun's escalating threats.
"They're professional informants. They get paid, they get rewards," said criminal defense attorney Tom Durkin.
While not involved in Mr. Hassoun's case, defense attorney Tom Durkin has represented accused terrorists from Gitmo to Chicago.
In many of those cases, the FBI has used informants. They are people who Durkin says have a strong motive to steer a suspect toward criminal activity.
"Is this person planting seeds in other people's minds to do something they otherwise wouldn't do?" said Durkin. "Obviously no one is going to complain if no bomb went off in Wrigleyville. In the same breath, was there really ever going to be a bomb go off in Wrigleyville?"
The FBI insists it always verifies information provided by paid sources.
In the Hassoun case, the criminal complaint says undercover agents gave Hassoun several opportunities to walk away from the Wrigleyville bomb plot, at one point saying "you don't have to do it, you can leave at any time." He said, "I can do it."
Hassoun's attorney counters it was the FBI's source and undercover agents who steered the plan.
"Would it have happened, no? He's not capable of coming up with these ideas," said Auerbach.
In deciding to keep Hassoun locked up, the judge said she found it hard to imagine a more serious crime with more potential for danger. She may also order a psychological exam.
While born in Beirut, Hassoun reportedly grew up on the Ivory Coast in Africa during the civil war, only to return to Lebanon during bombings there.
His attorney suggests that may explain his lack of appreciation for the seriousness of the violent talk.