That's certainly what was more likely the case some years ago. Interesting that you slip in the "and/or ownership if(sic) firearms" as a qualifier.
Times, they are a-changin':
"Dozens of federal agencies now have Special Weapons and Tactics (SWAT) teams to further an expanding definition of their missions. Its not controversial that the Secret Service and the Bureau of Prisons have them.Department of Agriculture, the Railroad Retirement Board, the Tennessee Valley Authority, the Office of Personnel Management, the Consumer Product Safety Commission, and the U.S. Fish and Wildlife Service?"
Source: The United States of SWAT
http://www.nationalreview.com/article/376053/united-states-swat-john-fund
the and/or means ownership of firearms would probably make swat serve it even without a history of violent convictions...but normally you try to stop the suspect away from the location...like in a car.
I have no idea why BLM would have a swat. But I am a lowly street cop so that is way out of my lane of travel.
IT's time to demilitarize 99% of all federal agencies, ALL State & Local police forces all the way down to the locals. Only a few federal agencies need armed police. The ones needing this type equipment the most and has true justification is The Border Patrol. You'll notice they can barely have side arms.
I live in a county where TVA has several major assets. Over a decade ago I can remember hearing on my scanners TVA Security monitoring local Sheriff Dept Radio Comms and in some cases responding as back up to their calls. A new sheriff ended that issue.