How did they do it?

The "Scream" and "Madonna" has been recovered by norwegian police today. Although I´m happy these nationals treasures are back, and also hope that it has been a lesson for the poor security in Norwegian museums, I can´t help but wonder how on earth the police managed to find the paintings. They have been missing for over two years and all the people thought to have anything to do with the stealing of these paintings, are now in police custody. So what did the police do? They say no ransom has been paid, wonder if they´re lying? Was it an anonymous tip maybe? Have they known all along where the paintings were? I know they could have gotten them earlier, but they moved too slow and the paintings were moved. The police wont speak of this operation, not yet anyway. It can´t be just good ol´ policework, now can it? The Norwegian police just isn´t that good! Or, hopefully, I´m mistaken!