Reading about the Munch theft, I found this story on the biggest art heist in American history:
wow. Half-a-billion in art masterpieces, missing for 14 years, and we are no closer to solving the crime?
buh-bye, Scream. 
Those pieces are almost certainlyin the hands of one or more private “collectors”, and unless one of their friends narcs on them, they are hidden away for good.
The last time a copy of the Munch painting popularly known as “The Scream” was stolen, there was a ransom request that failed and the painting was recovered.
Munch painted several copies of his most important works. The one stolen last weekend was not the same one stolen last time.
If this was done for ransom, the painting will probably be recovered. If it was for a collector, it is gone. There is really no black market for something that famous.