Federal prosecutors have subpoenaed documents involving a state senator from DuPage County as part of an ongoing criminal investigation that has led to charges against the former leader of Chicago’s Teamsters labor union.

A federal grand jury sent a subpoena for government records to the Illinois Senate for documents relating to Democratic Sen. Tom Cullerton, a three-term lawmaker who last year spearheaded the legislative response to fatal Legionnaires’ disease outbreaks at the state veterans’ home in downstate Quincy.

The Feb. 5, 2019, subpoena sought Cullerton’s personnel file as well as records regarding his legislative attendance; reimbursements for travel, lodging, meals, cell phone and vehicle allowances; and “all emails to and from” the senator between Feb. 1, 2013, and March 31, 2016.

Cullerton has not been accused of wrongdoing. Reached Wednesday, he declined to discuss the subpoena publicly and referred questions from WBEZ to the U.S. attorney’s office in Chicago.

A spokesman for U.S. Attorney John R. Lausch, Jr., whose office subpoenaed Cullerton’s records, did not comment on Wednesday.

During the three-year period in which investigators are seeking records, Cullerton — now chairman of the Senate Labor Committee — disclosed in his state economic interest statements that he had received income as an “organizer” for Teamsters Joint Council 25.

The labor umbrella group comprises 26 locals and more than 100,000 members in Illinois and Northwest Indiana, including 4,600 who work for Illinois state government.

Annual spending reports the union filed with the U.S. Department of Labor for calendar years 2013, 2014 and 2015 showed Teamsters Joint Council 25 paid Cullerton $182,800 for that role, nearly doubling the senator’s cumulative pay from the state during that period, records show.

Teamsters Joint Council 25 has come under scrutiny after a sprawling criminal investigation yielded a 13-count extortion and tax fraud indictment in 2017 against its politically connected former president, John Coli Sr., who headed the organization from 2002 to 2017.

Federal prosecutors allege Coli was trying to extract $350,000 in kickbacks from two firms.

One was the Chicago film studio Cinespace, a one-time state grant recipient where a series of network television programs are filmed, including NBC’s Chicago Fire and Chicago P.D. The government accused Coli of threatening work stoppages and labor unrest at the studio, which employs Teamster members, unless Cinespace paid him off.

Coli has pleaded not guilty. His case has not yet gone to trial.

A lawyer representing Coli, who attained prominence in national labor circles and was an early backer of Chicago Mayor Rahm Emanuel, did not respond to WBEZ’s requests for comment.

Government filings involving Coli and the February subpoena seeking state records related to Cullerton share an identical grand jury case number and the same federal prosecutor. That suggests the probe involving both cases is the same, according to a former federal law enforcement source interviewed by WBEZ.

State campaign records show Teamsters Joint Council 25 and other Teamsters-affiliated groups donated at least $95,000 to Cullerton between 2012 and 2018. Joint Council 25 hosted a fundraiser for the senator in December 2017 that it said raised more than $70,000 for Cullerton, according to its website.

The council’s current president, Terrence J. Hancock, did not respond to a WBEZ message left at his office regarding the senator. In 2017, Hancock described Cullerton as “an upright and honest citizen” and a “reliable and concerned state senator.”

After a WBEZ investigation into Legionnaires’ at the Illinois Veterans Home in Quincy launched in late 2017, Cullerton was instrumental in helping push through a series of legislative responses to how the public health crisis was managed by former Republican Gov. Bruce Rauner’s administration.

Cullerton, a veteran of the U.S. Army and a frequent critic of Rauner, co-chaired legislative hearings on the Quincy outbreaks, which were linked to 14 residents who later died from Legionnaires’ or ensuing complications, and the sickening of dozens more residents and staff between 2015 and 2018.

Cullerton passed a resolution for a state audit into the outbreaks, which was released last month.

He also backed legislation to require 24-hour public notice of infectious disease outbreaks like Legionnaires’ at state veterans’ homes, and an increase in potential damage awards to $2 million for victims’ families who have sued the state over the fatal outbreaks.

Dave McKinney and Tony Arnold cover state politics and government for WBEZ. Follow them @davemckinney and @tonyjarnold. WBEZ investigative reporter Dan Mihalopoulos contributed to this report.