If I got a letter like that, I’d find out who is in the outfit and start data mining all their public info looking for delinquent real estate payments, etc. Send it all back to them. See how they like it.
At a fundamental level, this letter is a threat and sending a threat thru the mail is a crime.
Well, unless it’s a lib/prog/socialist/commie/dhimmiokkkrat endeavor then it gets a pass.
As we have learned through the IRS, the BATF, the FBI, numerous pols and bureaucrats and plutocrats, crimes among the ruling class are never punished. Punishments are for the non-protected class in Marxist culture.