I've been wondering quite a lot about this hypothetical situation. Situation: someone steals Bitcoins from one address, sends them to another address, then exchanges those Bitcoins for a fiat currency from an exchange.
Is there any way that they could be held liable for the theft, or are they protected by the general pseudonymity that exists within the Bitcoin network? (i.e. It couldn't be known that the supposed thief wasn't just sent the coins for whatever reason)
it would require some computer forensics and computer security gymnastics to be able to get them back. Legally there is no law protecting your asset. cryptocurrencies are the wild west right now and everything is more or less unregulated. buyer AND seller beware. Protect yourself as much as possible. Unless it goes mainstream and the dumb joe gets on board there is no legal statutes or penalties. At most you could get them on hacking your account, data and possibly identity theft but most law enforcement organizations are so computer illiterate that it would be difficult to get anything out of them.
At some point security firms will appear out of the cryptocurrency economy like Wells Fargo did in the Old West. They will protect your coins for a small fee. You can choose to hire them for protection or take the risk of fending for yourself.
But risk is where the money is made.