Out of curiosity, I looked it up. Evidently the US Departments of Agriculture and Education have their own police forces. But they’re not called police officers. They’re called inspector generals, and are considered law enforcement officers.
I suppose that eventually everyone in the United States will be either be a law enforcement officer or be under the surveillance of a law enforcement officer.
https://reason.com/2011/06/08/dept-of-education-swat-team-up/
Apparently the guy was involved in some type fraud. However, no need for the type of stuff when you could just do a traffic stop, take him into custody and go back to his house like adults.
The EPA also has armed enforcement.
I met one once through an aquaintance in a social setting while I was in California. Next thing you know he was showing off his concealed pistol to everybody.