The irony, of course, is teenagers post pictures of themselves engaging in embarrassing, sometimes illegal behavior on Facebook all the time.

So why shouldn’t Auburn police?

Three local teens have learned this lesson, as their illicit wandering through the Hilton Garden Inn, as captured by security cameras, was posted on the APD’s Facebook page for all to see. Lo and behold, the Facebook friends gave up the little ne’er-do-wells straightaway.

It was a victory for community policing – of the digital variety. Canvassing neighborhoods is police noir, compared to using consumer technology. Auburn police knocked on thousands of online doors for this investigation, faster than knocking on one in reality.

And in one swoop, they validated this social-networking experiment with real results. Now, maybe an old-fashioned gumshoe could have gotten the same result. But it would have taken longer, while lacking the gleeful irony that could only have come from Facebook justice.

LOL, you got busted on Facebook. Not by your BFF, but by the real-life police. They took technology that is teens’ second nature and used it against them.

Concerns about Facebook justice should exist, though. Investigative success shouldn’t, in our mind, embolden police to expand their horizons to trawl for possibly criminal behavior.

Although the technology lowers expectations of privacy, there’s something unsettling about law enforcement monitoring such pages as a matter of course, instead of necessity.

Certainly, people who post evidence of blatant criminal behavior on Facebook have it coming. Yet Internet-derived information, as we should all know by now, is often apocryphal, inaccurate, exaggerated or plain false. Pictures can be altered and messages misconstrued.

There’s a thin line between police work and privacy invasion in social networking, it seems, which should be identified and respected. Maybe the best description of it, in straightforward terms, is we don’t need the Facebook police, but the police on Facebook.

For situations like the Hilton Garden, for example, fast dissemination of information about a crime was able to generate information that led to the suspects. Online communities are growing powerful and broad. Police are wise to embrace them, just like any other.

But they should respect it, too. If police were peeking into the windows of our homes, it would violate the community’s trust and be self-defeating in the long term.

The same principle, it seems, should apply in a digital form to Facebook.