Picasso's picture stolen in Brazil

At Sao Paulo, picture drawed by Picasso and Bortinari were stolen. It is said that they are about 100000000 dollars together. The police says that the pictures were stolen by a collecter. I though that the museum should try to make the security system stronger. But I think how strong they make the system stricter, it is always not enough. Thieves will do anything to get the pictures.