Sidley Austin won’t have to turn over its notes and memos from its investigation of alleged sexual abuse at a suburban Chicago school district.

The Chicago-based 7th U.S. Circuit Court of Appeals found the documents were protected by the attorney-client privilege and the work product doctrine, the National Law Journal reports.

Plaintiffs in a civil lawsuit against the South Berwin School District had claimed they were entitled to the notes because Sidley was providing investigative rather than legal services.

But the court said in its opinion (PDF) that the law firm was hired not only to investigate claims of sexual abuse by an elementary school band teacher, but also to provide legal advice to the school board.

“Sidley’s investigation of the factual circumstances surrounding the abuse were an integral part of the package of legal services for which it was hired,” the court said. “The fact that the privilege is invoked by employees of a governmental entity rather than a private party does not change the analysis.”