Amid interrogations and office raids from Chicago to Springfield, Illinois’s powerful Democratic machine is under threat.

The raids of federal agents on at least nine homes and offices respond to an investigation of a broad network of corruption and patronage involving Commonwealth Edison, the state’s largest utility company and the political operation led by House Speaker Mike Madigan, Illinois’s most powerful Democrat, according to The Hill.

According to two people who showed up for interviews with the police, the officers were asking questions about Madigan, his political operation, and his associates.

Part of the investigation appears to focus on the ‘lobbyist army’ that Commonwealth Edison and its parent company, Exelon, employ in Springfield, some of whom allegedly won contracts for jobs in which they did not show up.

The companies publicly acknowledged having received at least two subpoenas seeking information about their lobbying practices in Springfield and their relationship with former state senator, Democrat Martin Sandoval, whose resignation will take effect Jan. 1, 2020.

During several raids in September at Sandoval’s office and residence, federal agents found information about Springfielders and their monetary interests, including video game tycoon Rick Heidner, highway paving tycoon Michael Vondra and the former Commonwealth Edison and its parent company, Exelon Corp, according to WBEZ Chicago.

Of the 23 lobbying companies Exelon paid to lobby on its behalf this year, 15 have ties to Madigan, WBEZ reported. Eight of those companies employ former aides to Madigan, five employ retired Democratic state legislators who served under Madigan, and two employ lawyers who worked for Madigan and at the same time lobbied for the utility.

The federal agents also raided the homes and offices of several prominent lobbyists who had contracts with Exelon.

In July, the FBI raided the home of Michael McClain, another ComEd lobbyist and one of Madigan’s closest confidants. In November, the Chicago Tribune reported that federal agents had wiretapped McClain’s phones, although it was not clear if Madigan was recorded in any conversation.

The FBI is also interested in the payments made to Quinn after he was fired from Madigan’s political operation. The Chicago Tribune obtained emails showing that McClain paid more than $30,000 to Quinn through ComEd lobbyists.

McClain finally withdrew from lobbying in 2016, although records show that ComEd continued to pay him hundreds of thousands of dollars for consulting services.

The centerpiece of the scandal is Mike Madigan, a leading figure in Illinois politics, where he has served as speaker of the state House for all but two of the last 36 years. He also served as president of the state Democratic Party since 1998.

The largely Democratic state of Illinois has been subject to scrutiny in recent years because of its large networks of corruption and the idea that many people have that it is okay for the state to make a personal profit.