[hinckley buzzard]

Because museums don't buy stolen goods. If they think it is stolen goods they will not buy it, and if they find out it is, they have to surrender it. This is why museums go through extensive research to establish provenance of a work of art. Sounds to me like this museum didn't do their job very well.

[Freedom4US]

They aren’t supposed to buy stolen goods, I understand that.

My point is, the mete fact that they “didn’t know it was stolen” does not confer legitimate title! It does mean (if true) they won’t be prosecuted, but they have no claim to ownership. This is black letter law.