The attorney-client privilege protects notes and memorandums that Sidley Austin wrote while investigating alleged sexual abuse by a music teacher, a federal appeals court said on Tuesday.

In an opinion issued Tuesday, the 7th U.S. Circuit Court of Appeals ruled that handwritten notes and memorandums relating to interviews produced by Sidley Austin lawyers in the course of their investigation are protected by the attorney-client privilege and the work-product doctrine, even though the lawyers weren’t handling the lawsuit that sparked the investigation.