I doubt it was the FBI. More than likely, the Postal Inspection Service, which investigates mailbox destruction. My grandfather was a postal inspector. And, yes, vandalizing a mail box is a federal offense.
I understand that anything with mailboxes is technically a federal offense, the story just doesn’t add up especially 20 years ago when private video would be basically non existent
The last hurricane blew my mailbox off its post. No postal inspector, much less the FBI, showed up. Sorry, couldn't help myself.
My wife told me that she thought it was the FBI. Like I said, it was before my time in this small community.