A federal judge has agreed to sanction City Hall in yet another lawsuit in which Chicago attorneys have been accused of withholding key records.

U.S. District Judge Thomas M. Durkin granted the sanctions Tuesday sought by Whitley Klingler, who filed a lawsuit over her altercation with someone who appeared to be a member of the Emerald Society police bagpiping band on the night of the 2014 St. Patrick’s Day parade. The incident is alleged to have occurred at the McDonald’s that used to be across the street from Wrigley Field

“The judge is correct that a mistake was made here, and we will determine the cause and take appropriate action, Bill McCaffrey, a spokesman for the city’s law department, said in an email. “The Law Department recently implemented a number of reforms that will prevent mistakes like the one that occurred here from being repeated in the future. These reforms include a requirement that the City’s counsel directly request and obtain all documents from IPRA. Such a direct and specific request should have resulted in the City’s outside counsel being aware, and receiving a copy, of the investigation in question.”

Despite indications from the city that there was no “known” investigation by the Independent Police Review Authority of the incident, Klingler purportedly learned IPRA “was present the night of the events.” Further, Klingler attorney Kellie Walters wrote that City Hall refused to turn over the name of the officer accused of assaulting Klingler.

Klingler claims she was originally told that the officer’s name was “Sean O’Dublan.” Later, she said she learned it was really Will County Sheriff’s Deputy Matthew Griebel.

A spokeswoman for the Will County Sheriff’s Department confirmed that officials there were aware of the lawsuit. She said Griebel was off duty at the time of the alleged incident, and it was handled internally by Will County officials, but she declined to comment further.

Chicago attorney Kenneth Battle argued that Klingler knew of the IPRA investigation because Klingler initiated it. He also wrote in a court filing that “unbeknownst to the Chicago Police Department, IPRA conducts approximately 5,000 investigations per year. It is meant to be an independent entity.”

But Durkin said Tuesday that “somebody messed up,” and he told attorneys for the two sides to try to agree on a fee.

Just last week, a federal judge indicated sanctions may be in order after city lawyers were accused of withholding information about a 2014 fatal shooting involving an officer targeted in a lawsuit over a separate matter. Officer Patrick Kelly is a defendant in a federal complaint filed by a woman who suffered a miscarriage after she was Tasered three times by a Chicago Police officer in 2013.

Former federal prosecutor Dan Webb was tapped early this year to lead a third-party review of the city’s law department after a senior attorney resigned in disgrace for concealing evidence in another police-shooting case.