FILE – In this July 26, 2017, file photo, Illinois House Speaker Michael Madigan, D-Chicago, speaks at a news conference at the Capitol in Springfield, Ill. (Justin Fowler/The State Journal-Register via AP, File)

SPRINGFIELD, Ill. (AP) — The top Republican in the Illinois House filed a breach of public trust charge against Democratic Speaker Michael Madigan, the longest-serving legislative leader in U.S. history.

The action Thursday came as a special committee began investigating Madigan’s alleged role in a decade-long bribery scheme at the state Capitol. The Justice Department’s criminal agreement with ComEd released in July included admissions by the utility giant that it engaged in bribery with a high-level lawmaker in exchange for favorable legislation. The lawmaker is identified only as the House speaker.

Madigan did not attend Thursday’s hearing and has denied wrongdoing. The process could result in discipline, including ouster.