WASHINGTON (AP) — The Homeland Security Department needs better rules over its use of Twitter, Facebook and other social media services to improve privacy and legal safeguards, the inspector general wrote in a report Friday.

The report cited confusion over “legal, privacy and information security boundaries,” including one case when its investigators were secretly but improperly monitoring people online to detect benefit fraud. Officials later realized the effort broke agency rules about using online tools for undercover work, and they stopped doing it.