I don't think he's an alt account. However, this does raise a good point - he could and should have made an alt by now to explain the situation if it was more complicated than simply taking the money and run. Sure, it doesn't strictly mean the worst has happened, but there's been over a year to come back to the very site he was advertising it on.
If he ever wants to come back and explain what happened, either on his account or an alt, I'll happily hear him out. But it's hard to give the benefit of the doubt at this point.