If it's stolen property, it's a tough situation. What should happen if someone steals the art and sells it through a fencer? Should that customer get to keep

If it's stolen property, it's a tough situation. What should happen if someone steals the art and sells it through a fencer? Should that customer get to keep it? If not, should it be taken from that customer and returned to its owner? It seems unlikely that's what's happening here, though. But it's an interesting question. I don't know how law enforcement usually handles that situation.