“Since 2003, it has been an honor of a lifetime to serve the State of Illinois and fight on behalf of the good people of the Southwest-Side of Chicago/Suburban West Cook,” he wrote.

“Respect for my constituents and the Senate has convinced me that this action is necessary in order to proceed without distraction to the important work that needs to be accomplished for the working families throughout the state of Illinois in the future.”

The raid on Sandoval’s office is one of many to hit Illinois officials in the past year. The September subpoena sought information on a slew of different individuals and businesses—from construction and transportation to utilities, video gambling, racing, and red light cameras.

Sandoval is the only lawmaker named in the subpoenas ComEd and Exelon received this year, part of what appears to be a wide-ranging federal probe of corruption in Springfield and elsewhere.

He has not been criminally charged.

Today's news sets off a race to finish Sandoval’s current term, which ends in 2023. The Illinois State Board of Elections will hold a special filing period Dec. 3 through Dec. 9 for candidates wishing to run in the March primary. Candidates must gather 1,000 to 3,000 petitions from 11th District voters before Dec. 9 and submit them to ISBE’s Springfield office.

Party officials must fill Sandoval's vacancy within 30 days of his retirement. With Senate President John Cullerton's expected retirement in January, that means two replacements for the Senate will be chosen around the same time. Sandoval's replacement will serve through Dec. 7, 2020.

As 13th Ward democratic committeeperson, Speaker Mike Madigan has the largest share of the weighted vote to replace Sandoval (just under 34 percent).

That's followed by former 23rd Ward Ald. Michael Zalewski, who has 23 percent of the weighted vote. Zalewski's home was raided by federal officials, who sought information on communications with Madigan and Commonwealth Edison.

Bridgeview Mayor and state Sen. Steve Landek and Sandoval ally Antonio Muñoz each have about 11 percent of the weighted vote. Ald. Ed Burke, facing several corruption charges, and former Ald. Zalewski's son, state Rep. Michael Zalewski, are also on the selection committee.