Approaching the center of town to pick up pizza last night, I saw a half-dozen police vehicles blocking off Main Street. I pulled into a parking lot both to figure out how to get to our dinner and to find out what was going on.

The instant a bystander told me what he had heard, I knew this police operation was almost certainly the result of a hoax known as Swatting, which starts with a fake 911 call reporting a non-existent life-threatening situation. It’s become an epidemic of late, targeting celebrities and online gamers, in particular.

While police had no choice but to take the threat seriously – more on that in a minute -- I was confident this was a hoax for two reasons: I have been reporting on the topic recently and the rumored details of the 911 call seemed far-fetched: a man claimed to be holed up in the closed Hopkinton Public Library with two hostages and a bomb. (Not only did I believe this was a Swatting, I said it out loud, so the editor of a local news site called HopNews decided I was worth interviewing.)

While no one was hurt, being on the scene did give me a two-hour look at the disruption and utter wastefulness these crimes can create (never mind that many have also carried a real possibility of getting someone killed).

Paul McNamara Police command center for "Swatting" incident last night in Hopkinton, Mass.

Dozens of law enforcement vehicles arrived in a steady stream, including Massachusetts state police and some from neighboring communities. Three or four of the SWAT variety, unmarked and black, eventually showed. The command center was in a pharmacy parking lot between the library and our vantage point, from which we could get only a glimpse of the library. There was a bomb-sniffing dog. The pizza shop I was attempting to reach and two restaurants were evacuated; all deprived of their important Saturday night receipts. A church service was cancelled. Traffic was snarled.

The assembling officers moved purposefully but without the heightened sense of urgency one sees in TV footage from active-shooter incidents.

Police say they received the first of the perpetrator’s two calls just before 5:30 p.m. When I showed up about a half-hour later, the SWAT vehicles had yet to arrive. It was clear that the police were waiting and marshalling resources prior to approaching the library.

Onlookers milling about the perimeter exchanged gossip, with many asserting as established fact that there was an ongoing hostage situation in the library. Four or five television news crews arrived.

At 7:30 or so a SWAT vehicle departed the pharmacy parking lot, turned left and headed toward the library; two officers in full gear visible through the open back doors.

Another half-hour of waiting passed. Then just after 8 p.m. it was obviously all over because car headlights were visible as traffic approached from the previously blocked off other side of Main Street. How police entered the library was not discernable from where we stood, but it wasn’t loud enough to be audible.

That was it: two-and-half hours of wasted tax dollars, lost revenue and needless disruption. (Not to mention that my kids and I never got our pizza.)

The police chief told the news crews it was all a hoax and that they would do everything possible to bring the perpetrator to justice.

If you’re thinking that maybe the police could have done differently -- namely less -- I’d suggest you add two other factors to your calculation.

First, there were two calls from the perpetrator. The first one claimed hostages and a bomb, and, we learned later, included a $50,000 ransom demand. In the next call, a few minutes afterward, the man demanded that police who had already responded back off, suggesting he could see them. Police knew the library was visible on at least two webcams. (And, yes, the second call could be simply part of an absent Swatter’s script, designed to bolster plausibility.)

But here’s the second factor to consider: The Hopkinton Public Library stands within eyesight of the starting line of the Boston Marathon, which will be run two weeks from tomorrow. The caller said he had a bomb. Enough said.