A former Jones Day partner has resigned from his high-ranking position within the Cook County State's Attorney's Office in Chicago after an internal review found that he referred work to his former firm at a rate higher than the municipality's standard general rate.

Cook County's state's attorney's office following an internal review that uncovered he referred work to his old firm at higher-than-normal billing rates.

Earlier this year, Jones Day touted Chaka Patterson's decision to join a dozen other former firm lawyers heading into public service positions. On Dec. 15, Patterson officially stepped down as head of the civil division in the Cook County prosecutor's office, which he joined in February after the election of Democrat Kimberly Foxx to head that office. Kent Ray, chief of the general litigation and advice division in the Cook County prosecutor's office, has taken over for Patterson as acting chief of its Civil Actions Bureau, according to local news reports.

The Civil Action Division handles nearly all of the civil suits filed against the city of Chicago and as its head, Patterson was able to refer cases to outside counsel when the Cook County prosecutor's had a conflict. Under city ordinances, hourly rates for outside legal teams are set at $185, unless there's a matter that needs a specialized attorney or if a judge orders a higher rate.

This was where the trouble began, according to the Chicago Tribune, which broke the news Dec. 15 about Patterson's resignation following an internal inquiry into legal expenditures.

Patterson reportedly referred two cases—a federal job discrimination suit and a federal wrongful conviction matter—to Jones Day at a rate of up to $500 per hour. Cook County records showed that the firm has already billed for more than $464,000, according to the Tribune, which noted that the fees come at a time of increased financial strain on public coffers.

Robert Foley, a state's Attorney's Office spokesman, said in a statement to the Tribune that the office launched an internal review that found Patterson “[had] referred significant business to his former law firm at a billing rate significantly in excess of the standard county rate.” Foley did note that the state's Attorney's Office had no reason to believe that Jones Day had done anything inappropriate.

A spokesman for Jones Day did not immediately return a request for comment on the matter, nor did Patterson.

Patterson joined Jones Day in May 2013 after two years working as an of counsel at Skadden, Arps, Slate, Meagher & Flom, where he represented clients in state's attorney investigations and litigation. Skadden hired Patterson in 2011 after he served as an associate general counsel and vice president at Chicago-based energy giant Exelon Corp.

Patterson also spent a brief time as a partner at Jenner & Block in Chicago, leaving the firm in late 2003 to become chief of the special litigation bureau in the Illinois Attorney General's Office, where he worked until heading to Exelon in 2006.

As for Jones Day, which has made headlines this year for its close ties to the Trump administration, the firm has previously hit back at municipalities questioning the value of its services. In March, Jones Day blasted the mayor of Detroit for threatening the firm with litigation over its role advising the Motor City in its bankruptcy case.

Jones Day earned nearly $58 million in legal fees for its role in that matter.