Back to the Diamond Heist in Belgium Antwerp 2003, it appears that at least one thief managed to disappear into the ether. The main man (he mistakenly thought they would not find out who did it and returned to the scene of the crime to clean up) got 10 years (of which I believe 6 were served), and the other 4 were sentenced to 5 years. They are all out of prison now and enjoying their stolen goods as far as everybody knows. The four thought they were safe in Italy since that country did not have a duty to give up criminals to Belgium.
Ah, the main guy was arrested a few years later and he had to serve the rest of his sentence. He was also supposed to compensate the victims of the heist, which he never did.


