A grainy video of four masked vandals running through an art gallery in Sweden, smashing sexually explicit photographs with crowbars and axes to the strain of thundering death-metal music, was posted on YouTube Friday night.

This was no joke or acting stunt. It was what actually happened on a quiet Friday afternoon in Lund, a small university town in southern Sweden where “The History of Sex,” an exhibition of photographs by the New York artist Andres Serrano, had opened two weeks earlier.

Around 3:30, half an hour before closing, four vandals wearing black masks stormed into a space known as the Kulturen Gallery while shouting in Swedish, “We don’t support this,” plus an expletive. They pushed visitors aside, entered a darkened room where some of the photographs were displayed and began smashing the glass protecting the photographs and then hacking away at the prints.

The bumpy video, evidently shot with a hand-held camera by someone who ran into the gallery with the attackers, intersperses images of the Serrano photographs with lettered commentary in Swedish like “This is art?” before showing the vandals at work.