CHICAGO, May 28 -- Former U.S. House Speaker Dennis Hastert has been charged here Thursday with lying to the FBI about hush money withdrawals.

The Chicago Tribune Thursday quoted federal prosecutors as saying that Hastert agreed to pay 3.5 million U.S. dollars to a longtime acquaintance to "compensate for and conceal (Hastert's) prior misconduct" against the acquaintance from years earlier, and then lied to the FBI about his cash withdrawals from several banks.

Though details of the relationship and Hastert's alleged wrongdoing were provided, the indictment clearly indicated that Hastert's early career as a teacher at Yorkville High School was key to the charges, the local newspaper quoted Jeffrey Cramer, a former federal prosecutor and now head of the Chicago division of the private security company Kroll, as saying. Cramer said, "3.5 million dollars is a lot of money to keep a secret hidden."

Hastert, 73, has been charged with structuring currency transactions to evade currency transaction reports and making a false statement to the FBI, counts that each carry a maximum penalty of five years in prison and a 250,000-dollar fine if convicted.

From June 2010 to April 2012, Hastert made 15 withdrawals of 50,000 dollars each from his bank accounts and paid the acquaintance that cash about every six weeks, according to the indictment.

After bank representatives questioned Hastert about the withdrawals in 2012, he began illegally structuring the cash withdrawals in increments of less than 10,000 dollars to evade bank reporting requirements, the indictment said.

The FBI began investigating the cash withdrawals in 2013. When questioned by the FBI about the withdrawals last December, "I kept the cash. That's what I'm doing," Hastert was quoted as saying to the agents.

Hastert served as House speaker for eight years from 1999 to 2007, the longest-serving Republican House speaker in history. He resigned from the board of directors of the Chicago-based CME Group on the same day the indictment was announced.