If we needed a reminder of the really dark side of cybercrime, beyond just stealing your money or identity, consider the experience of reporter Brian Krebs on Thursday afternoon: He opened his front door and found a squad of Fairfax County police officers aiming guns at him.

Krebs, a former Washington Post reporter who left the paper three years ago, was the victim of “SWATing,” according to a story first broken by the Ars Technica blog. I wrote about it for Saturday’s print edition here, and Krebs gave his own first-hand account here. “SWATing” is the practice of phoning in a false police report causing them to send heavy (or SWAT team) response, often by “spoofing” the caller ID to disguise the source of the call. I wrote about spoofing in another Fairfax case a few years back, along with e-mail hacking.

But Krebs is the authority on this stuff and his blog is required reading if you’re interested in the security of your information. After leaving The Post, he launched Krebs on Security, which contains a fascinating flow of news and alerts about what’s going on with bugs in the latest software, hacking scandals and assorted sleaze in the “underweb” of complicated cybercrime. Krebs has won numerous awards for his journalism, including two last month from the RSA Conference for his blog, and he’s already in the Security Bloggers Hall of Fame.

After writing an article on Wednesday about an online company that appeared to be selling illegal access to consumer credit reports, he received a phony threat letter from the FBI; then an attack trying to take down his Web site; and then the visit from the police. The “underweb” is serious.

But Krebs is serious too, and undeterred. “The World Has No Room for Cowards,” he headlined his piece on the SWATing visit from Fairfax police (who didn’t actually send SWAT, and quickly deciphered and deescalated the situation). So bookmark this important Fairfax journalist. Don’t let the underweb win.