From The Chicagoist (found by xeno on io9):

A (now ex-) guard at the Carnegie Museum in Pittsburgh has been charged with slashing a painting on loan to the museum from our very own Art Institute. Art Institute restorers are trying to see if the painting is salvageable, but police say it's damaged beyond repair. Neither museum will comment on how much the painting is worth, but reports say Vija Celmins's "Night Sky #2" is worth around $1.2 million. Well, it was.

A few points:

1. There is no "Carnegie Museum." There are four Carnegie Museums, plural. The Science Center, the Warhol, the Museum of Natural History (MNH), and the Museum of Art (MOA). The painting is (was) on display at the 55th Carnegie International at the Carnegie Museum of Art, not the "Carnegie Museum." MNH and MOA share one street address (4400 Forbes Avenue), so it's an easy mistake to make if you haven't spent any time in Pittsburgh. Most people haven't.

2. The guard, Timur Serebrykov, is, according to a source who's worked for both MOA and MNH, Russian. The artist is Latvian. This probably has far more to do with the defacing than the content itself.

3. This isn't the only thing that's been defaced, broken, or destroyed on the floor of 4400 Forbes over the past few months. It just happens to be the most expensive, and the most high profile.