the only thing that could help you through this is getting them to download and run YOUR version of a bitcoin wallet, that might provide you multiple places where they see the balance because you could control the network that the daemon at their home pc connects to.
I highly doubt that would work as any sane person looking to store a large amount of Bitcoin is going to look for a well reviewed and highly recommended wallet. In fact, there's probably a good chance that they would use a hardware wallet along with the software that the wallet maker recommends so this would be very difficult to pull off.
in the end you would catch a lot of lawsuits, but the way the law is here at this time you would not catch any criminal charge unless it is tampering with their PC(maybe?). it is set up here in the USA that if they knowingly transfer BTC to you, whether under false pretenses or not, you are fine.
Wouldn't this kind of scam be considered fraud which is a criminal offence?
that is why when you see people on here bitch that they have been scammed out of BTC, they can simply keep whining. Crypsty got nailed because their site made claims to "Securely store" the commodity of Bitcoin and other alts, thus acting as a class 3 MSB and underclass 4 securities foundation. if you sucker someone into giving you bitcoins, then they were simply stupid and deserve the loss. if you tell them, via website or any other communication, that you are "storing", "securing", "holding"(while using the term investment), or "using secure transfer", then those terms, exactly as i just said them, put you in the hands of the SEC and InterSync
This is not that the victim is giving you Bitcoin, but rather they are giving you fiat (or something else) and you are giving them Bitcoin. Except the fraud here is that you are not actually giving them Bitcoin, only making them believe that Bitcoin was sent.