This is my own personal opinion and I have no proven facts, but I feel that the reason banks and credit card companies never pursue a fraud through the police is because a lot of it is internal and they do not wish their systems to be scrutinized in the light of day, thereby revealing their flaws.
I know there is an argument for saying the less people know how they operate the more chance of catching someone, but do they ever, or are they as it seems content to just keep on refunding fraudulent transactions, as I doubt they do this out of the goodness of their heart someone pays i.e you and me in fees and interest charges.