I've had the FBI at my door twice in my life. In both cases they were dressed in plainclothes (business casual), showed their badges, and gave me their business

I've had the FBI at my door twice in my life. In both cases they were dressed in plainclothes (business casual), showed their badges, and gave me their business cards after I refused to talk to them without a lawyer present (and never came back). No SWAT team, no brandishing of firearms (though they were armed). Scarily pleasant talk. (I don't remember what their cars were. Nice sedan I think, not SUV.) "Hello XXXX, We're here to ask a few questions about XXXX and were wondering if we could come in for a few minutes and talk with you" "I'd prefer not to talk to law enforcement without a lawyer present." "It's only a few questions, we won't take up too much of your time" Repeat with different niceties for awhile, no threats. Then, "Okay, I'm Special Agent XXX and here's my card if you change your mind" -- On the other hand I've been arrested twice by local cops for refusing to talk to them, often with a bit of, ermmm, physical persuasion involved. FBI are the smooth talking salesmen of the law enforcement world, at least when they want you to cooperate with them and don't have anything on you. They aren't really in the business of running around and cracking heads like your local beat cops. But this story was "just" a visit from local cops, local terrorism task force, I think