CHICAGO — Former U.S. House Speaker Dennis Hastert is challenging a decision by the Teachers’ Retirement System to terminate his pension and go after a refund of $222,808, arguing the federal charges he was convicted of last spring are not directly connected to his time as a teacher.

Hastert, of Plano, is serving 15 months in a federal prison in Minnesota after pleading guilty to money laundering charges involving payments to cover up sexual misconduct.

At his April 27 sentencing, Hastert admitted he had sexually abused teenage boys he’d taught and coached at Yorkville High School, where he worked from 1965 to 1981.

His attorney wrote that the statute of limitations for any such offense expired long before the federal indictment was issued, and added that an Illinois Appellate Court decision found it is unlawful for TRS to seek to recoup benefits paid prior to the date of conviction.

At the time Hastert worked in Yorkville, Illinois’ statute of limitations on abuse cases was three years. It later was expanded, and Illinois Attorney General Lisa Madigan is using the Hastert case in her push to further lengthen the time limit during which charges are allowed.