As far as the DoE goes I pretty sure NNSA contracts out the majority of their security positions. I think this is a somewhat recent development because I think they used to have a highly respected security force. Who would you prefer to have guarding DoE nuclear sites?
That's by definition a paramilitary, but they aren't SWAT teams, e.g. their formal rules of engagement are very different.
For that matter, informal, I doubt they get off on killing dogs (if you don't know about that, search on swat puppycide, Radley Balko has written a lot on it).
