In Illinois, another plot to commit mass murder foiled long in advance by authorities: Alleged would-be bomber described as humble, polite.

Over the two years that authorities tracked Michael C. Finton, accused Thursday of trying to bomb Springfield’s federal courthouse, they gave Finton plenty of chances to drop the idea. …

Authorities say Finton tried Wednesday to ignite what he thought was a huge quantity of explosives contained in a van parked near Sixth and Monroe streets. Finton allegedly expected the resulting blast to kill everyone in the Paul Findley Federal Building, plus “take out” an office of U.S. Rep. Aaron Schock across the intersection.

As it turned out, however, law enforcement authorities had been aware of Finton’s plans for more than two years, the affidavit said. As a result, a man Finton allegedly thought was a low-level operative of the al-Qaida terror network was actually an undercover FBI special agent, and there were no explosives in the van.

Instead of the van blowing up when Finton dialed a cell phone number, agents swooped in to arrest him.

On Thursday, Finton, who authorities said also used the name “Talib Islam,” was brought before a federal judge in the same building he allegedly had targeted.