Sly Cooper: Thick as Thieves

(Since I miss playing the game :( I have decided to create a new fanfic of sly cooper, let me know if I should continue...)

After a few years after Sly Cooper and Carmelita had a happy marriage, good life and things seem to be normal. But sly felt something was missing in his life, maybe it's was years of losing touch with his inner thief, but he was unsure of his own feels at this moment. One night in Paris a Museum was robbed! Carmelita suspect it to be him, but sly knew he wasn't there. Who was this Mysterious raccoon and what did they take?