In a June 2, 2023 interview, FBI Security Division Assistant Director Jennifer Moore claimed her office didn’t leak the letter, but she never investigated.
https://judiciary.house.gov/media/press-releases/judiciary-republicans-release-transcripts-interviews-fbi-security-clearance
In fact, it’s not clear that anyone at the FBI or DOJ ever investigated whether the leak came from any of their staff—such as the supervisory special agent in FBI Congressional Affairs sharing documents with Goldman’s staff.
https://x.com/tristanleavitt/status/1798792420563259467