by Todd Feurer, CBS Chicago web producer

CHICAGO (CBS) — Two months after FBI agents raided his office in Springfield and his home in Gage Park, Illinois State Sen. Martin Sandoval has announced his plan to resign, effective Jan. 1.

In a letter submitted to the Illinois State Board of Elections, Sandoval, a Democrat from Chicago, said he was resigning “with heavy heart,” after having served more than 16 years in the Illinois Senate.

“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,” Sandoval 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 working families throughout the state of Illinois in the future.”

State Sen. Martin Sandoval

Illinois State Sen. Martin Sandoval. (Credit: CBS 2)

Federal agents raided Sandoval’s office at the Illinois State Capitol in Springfield, and his home in the Gage Park neighborhood, on Sept. 24. Agents could be seen walking out of the Senate Democrats’ offices carrying computer equipment, cardboard boxes, and brown paper bags marked “evidence.”

Agents also removed boxes of evidence and a computer from his home in Gage Park.

CBS 2 Investigator Megan Hickey has reported federal investigators have been digging into Sandoval’s years-long relationship with energy utility ComEd and its parent company, Exelon.

The company acknowledged in October that they had been subpoenaed for “records of any communications” with Sandoval. A representative of the U.S. Attorney’s Office for the Northern District of Illinois, which filed the subpoena, declined to discuss it. A ComEd representative said the company intends to comply with any and all inquiries, and they’ve formed a special oversight committee to oversee it.

Exelon executive Anne Pramaggiore stepped down from the company just days after the utility revealed the subpoena. Pramaggiore had been CEO of Exelon Utilities, which oversees the energy giant’s six local gas and electric utility companies.

Sandoval is a member of the Energy and Public Utilities committee, and his relationship with ComEd goes back to 2007. Since then, his campaign has received $26,250 in donations, making him one of the top 25 recipients of ComEd donations during that period.

Sandoval’s other connection to ComEd is his daughter, Angie, who according to her Linkedin profile has been working for ComEd for nearly seven years – taking on the role of senior account manager in June.

According to a copy of the warrant from the raid on Sandoval’s office in Springfield, federal authorities were seeking “items related to any official action taken in exchange for a benefit.” According to a receipt provided after the raid, agents seized three computers, an iPad, five iPhones, seven USB drives, a Sandoval campaign spreadsheet, and several other items.

The warrant indicated the feds were seeking materials related to ComEd and Exelon, Cook County Commissioner Jeff Tobolski, slot machine company Gold Rush Gaming, red light camera company SafeSpeed, businessman Michael Vondra, video gambling company Gold Rush Gaming, several unnamed Illinois Department of Transportation officials,  Sandoval’s public relations firm Puentes Inc., and several other individuals and businesses.

Just days after the raid on Sandoval’s office, federal agents also raided the village halls in west suburban McCook – where Tobolski is mayor – and Lyons, as well as the insurance company owned by the family of Lyons Mayor Christopher Getty. The same day as those raids, the feds also visited the village hall in Summit.

The Sandoval warrant paints a picture of a wide-ranging investigation of the senator and his associates.

Vondra and his businesses have made campaign contributions to Sandoval, his daughter Angie, and many other Illinois lawmakers.

Gold Rush Gaming is a major video gambling company owned by Rick Heidner. According to published reports, Heidner also is a co-owner of Playing in the Park LLC, which recently won approval for 12 harness racing dates at a proposed racing track and casino in Tinley Park in December 2020.

Neither Sandoval nor anyone named in the warrant has been charged with a crime.

Sandoval resigned as chairman of the Senate Transportation Committee in October. As Transportation Committee chair, he had been a chief negotiator for a $45 billion statewide infrastructure improvement plan signed into law in June.

Gov. J.B. Pritzker had immediately called for Sandoval’s resignation.

“We must assure the public that this work is on the up and up corruption and self-dealing will not be tolerated,” Pritzker said last month.

After Sandoval steps down from his Senate seat, Democratic committeemen in his district must pick a temporary successor within 30 days, according to Illinois State Board of Elections spokesman Matt Dietrich. That successor would serve through Dec. 7, 2020, while an election is held to fill the seat long-term.

Meantime, the Illinois State Board of Elections will hold a special nominating period for candidates who wish to fill his seat for the remainder of his term.

Nominating petitions will be collected in Springfield between Dec. 3 and Dec. 9. Candidates who wish to run in the primary election on March 17, 2020, must submit 1,000 to 3,000 valid signatures of registered voters who live in the 11th District in order to get on the ballot. Whoever wins the subsequent general election on Nov. 3, 2020, would then serve the remainder of Sandoval’s current term, which expires on Jan. 11, 2023.

CBS 2’s Charlie De Mar contributed to this report.