The Illinois tollway's inspector general resigned unexpectedly Thursday, officials confirmed.
Tracy Smith's move comes as the Illinois attorney general's office is raising questions about the performance of Smith even as another agency defended her record.
"We're seriously concerned about her conduct as inspector general," a spokeswoman for Attorney General Lisa Madigan said this week.
Tollway spokeswoman Joelle McGinnis confirmed that Smith submitted her resignation but gave no details on it.
The attorney general office's criticism concerns a college friendship between Smith and Illinois State Toll Highway Authority Chairman John Mitola's wife. Madigan's staff did not elaborate on the issue or say if any action was planned.
Smith told the Daily Herald there is no conflict of interest.
Mitola in a Wednesday e-mail said "the notion that she was recommended due to an association she had with my wife from 15 years earlier in law school is ridiculous and is an insult to her background." He called any allegations against Smith mean-spirited.
Smith confirmed that she and Marcy Mitola were classmates in law school and "like a lot of old college friends have remained friendly over the years."
"No relationship exists that would prevent me from doing my job effectively," Smith wrote in an e-mail.
In her capacity as inspector general, Smith, a tollway employee, is empowered to root out fraud and corruption.
Madigan's office would not say if its concerns rose from a tollway inspector general's office review of an ethics complaint involving John Mitola and hiring decisions. Smith concluded any allegations of impropriety were unfounded.
James A. Wright, executive inspector general for the agencies of the Illinois governor, called Smith a professional who was "trained and nationally certified. We trust that when a real or potential conflict of interest does present itself, she will bring it to the attention of this office," he said in an e-mail earlier this week.
Smith was hired in 2005. The relationship between the two women was not publicly known and came as a surprise to some board members.
News of the resignation followed on Thursday the tollway board's first meeting with recent appointments by Gov. Pat Quinn.
Quinn had promised to clean house at the toll authority in the winter after he became governor. He replaced ousted Gov. Rod Blagojevich, who is facing corruption charges including allegations he tried to extort donations from a contractor in connection with tollway projects.
Newly appointed board Chairman Paula Wolff talked about priorities she shared with Quinn, including environmentally friendly projects and the "need for transparency and openness" in government.
The other incoming officials are tollway directors Bill Morris, former Waukegan mayor, and Aurora May or Tom Weisner.