Sami Samir Hassoun is accused of making his attempt after the Dave Matthews concert at Wrigley Field early Sunday morning, but the bomb was a harmless fake, provided to him by federal undercover agents, the Chicago Sun Times reported.
Over the summer Hassoun, 22, allegedly brainstormed different methods of terrorizing Chicago, including unleashing a virus, poisoning Lake Michigan, bombing Daley Plaza, attacking police officers or assassinating the mayor, the newspaper said.
But the FBI was onto him from the start, planting an informant and undercover agents to record Hassoun's every move, the Chicago Tribune reported.
Hassoun wasn't motivated by religious or political views, authorities said, but rather by a bizarre desire to undermine the mayor's political support and allow an associate to take control of the city.
He also hoped to profit from the scheme by being paid for his terrorism work by supporters, authorities said.
Steven Strauss, owner of a bar near the ballpark, said the entire neighborhood near Wrigley Field was overrun with concertgoers and college students Saturday night.
"It's scary to think of what could have happened," he said Monday night at the bar. "You have 40,000 people converge on Addison and Clark on a busy night."