A watchdog says the Homeland Security Department needs better rules for its Twitter and Facebook accounts and other social media to avoid breaking the law.

A report released Friday says that in one case, investigators in a DHS office were secretly monitoring people to detect benefit fraud.

But officials realized that the effort broke their rules about using online tools for undercover work, and they stopped doing it.

The report comes from the agency’s internal watchdog. In response, the department said it monitors Twitter accounts during natural disasters and police incidents. Once, officials in a child abuse investigation found a photo posted online and used the license plate to quickly make an arrest.

(AP)