The federal grand jury investigation into veteran Chicago Ald. Carrie Austin is looking into a wide range of matters, including her family members, the top aide in her office, campaign finances, and even the use of food stamps, according to court records obtained by WBEZ.

FBI agents carried out a surprise search Wednesday at Austin’s South Side ward office. The alderman has been on the City Council for 25 years and was a staunch ally of former Mayors Rahm Emanuel and Richard M. Daley.

A federal subpoena shows the grand jury probe has been going on since 2017 and its scope is broad. Authorities have sought “all items related to” the alderman herself and a long list of individuals and subjects, including:

• “Family members”

• Austin’s chief of staff, Chester Wilson, Jr.

• “Campaign contributions”

• “Cook County property tax assessments”

• “Link, SNAP and food-purchasing assistance”

• “Tax-increment financing”

SNAP, which stands for Supplemental Nutritional Assistance Program, is the name of the federal government’s food stamp program. The state of Illinois issues LINK debit cards to low-income people who qualify for SNAP, so they can buy food with them.

Austin is paid $120,384 a year as alderman of the 34th Ward, which includes parts of the West Pullman, Washington Heights, Morgan Park and Roseland neighborhoods.

The records obtained by WBEZ reveal that investigators are probing not only the construction and purchase of Austin’s home in the Renaissance Estates subdivision. The feds also were trying to get documents pertaining to all other “development projects in the 34th Ward” and the use of taxpayer subsidies from the city for real estate initiatives.

Austin has not been charged and could not be reached for comment Sunday. In an interview last week with CBS 2, she said she had done nothing wrong.

Wilson also could not be reached for comment. He has worked in the alderman’s office for almost 24 years, according to his online job-networking profile on LinkedIn. There, Wilson wrote, “I truly believe, as President Obama said, that if you take care of the community, the community takes care of you.”

Five years ago, Wilson received a pardon from then-Illinois Gov. Pat Quinn for a 1993 conviction for concealing and misrepresenting a vehicle’s identity, the Chicago Tribune reported.

Wilson is the second highest-paid aide to any Chicago alderman, with an annual salary of more than $118,000, according to city records.

On Wednesday at Austin’s office, a large group of stone-faced federal agents took part in the raid, hauling away boxes of documents. The FBI’s spokeswoman in Chicago confirmed that agents executed a search warrant at Austin’s office. But authorities declined to describe the potential criminal activity that prompted them to ask a federal judge to authorize the raid.

WBEZ first reported Wednesday that the investigation into Austin is not related to the ongoing corruption case against the sole alderman with greater seniority than her, 14th Ward Ald. Edward Burke.

Burke is accused of bribery, racketeering and attempted extortion, allegedly leveraging his political power to drum up business for his private law practice. He entered a not-guilty plea and has vowed to fight the charges.

Austin, 70, is the vice chairwoman of the Cook County Democratic Party and has been on the City Council since Daley appointed her to replace her husband, Lemuel Austin, when he died in 1994. She was re-elected with more than 54 percent of the vote in the February election.

For the past eight years under Emanuel, Austin headed the Council’s Budget Committee, which oversees how the city raises and spends more than $9 billion a year.

Despite backing Toni Preckwinkle in the mayoral race to replace the retiring Emanuel this year, Austin offered to be as loyal to new Mayor Lori Lightfoot as she had been to Emanuel and Daley.

But Lightfoot – who has promised to bring reform to a City Council that’s been riddled with corruption for decades – stripped Austin of the top Budget Committee post and gave her the chairmanship of a far less important committee, even before this federal investigation came into public view with Wednesday’s FBI raid.

Even as more and more old-style Chicago politicians have fallen to reform-themed challengers, Austin has remained an unabashed defender of nepotism in government.

She hired her son Kenneth Austin to oversee Streets and Sanitation Department work in her ward in 2017. He had been forced from another city job by allegations of wrongdoing from the city’s independent inspector general, Joe Ferguson.

Kenneth Austin began working again for the city, as his mother’s Streets and Sanitation ward superintendent, despite lacking a valid driver’s license. His license had been revoked because he owed child support payments. Carrie Austin paid her son’s debt, allowing him to regain his license and continue to work for the city, which now pays him more than $79,000 a year.

Another son of the alderman is an assistant commissioner in the Streets and Sanitation Department, with an annual salary of nearly $107,000.

Austin also has shown no patience for those who criticize her or the mayors whom she has supported steadfastly.

A year ago, she yelled at protesters who showed up at a fundraiser for her and the other African-American aldermen. The confrontation was captured on video and posted on social media.

“Shut up!” Austin said, using a microphone to blast opponents of Emanuel’s plans for a new training academy for police. “If anybody else wants to protest, you’d better take it outside, because I guarantee you ain’t seen no gangsters like this city’s aldermen.”

Laughing along with other aldermen as a protester was dragged out of the Black Caucus event, Austin added, “I guarantee you we can throw it down.”

Dan Mihalopoulos is an investigative reporter at WBEZ. Follow him on Twitter at @dmihalopoulos.