What it sounds like to me.

Before 9/11™ or even TWA 800, experienced this on UA FCO-MIL-IAD. The stop in Milan was supposed to be 20 minutes, barely long enough to load pax for the transatlantic leg. (No one then paid U.S. carrier prices just to go FCO-MIL.) Instead, we were told to exit the plane as rapidly as possible, bringing all carry-on with us. Exiting was not rapid, because some kind of LEOs were running all carry-ons through an x-ray set up in the jetway right outside the plane, clearly not its regular location. Two hours and a gate change later, we were back on the same 747—too many pax to tell if anyone was missing. Much speculation about bank robbers/jewel thieves/etc. but we never found out.

If there's a specific reason, and warrant or equivalent, to do this to catch a bad guy I have no objection. For random "because we can" snipe hunts, I do.