in short IF insider job. keep $5.3mill and always be looking over shoulder for rest of life, not only by ex-wife investigating but also authorities and customers. or return $4.5m keep $700k and be at peace. settle all debates/debts with authorities, ex-wife and customers
I doubt there can be any peace even if some document is signed, I assume it is already investigated as a crime by authorities, so nothing can be changed here. Now imagine instead of stollen BTC, someone is kidnapped and he is going to be freed for 1750 BTC and some signed document. It is obvious once crime is investigated by authorities, nothing can change, so doesnt make sence returning the BTC back unless it is inside job to make Cryptsy liquid and operational again.