I spent a bit of time the last few months looking at Craigs List, looking at the ads for used higher end bikes, specifically Litespeeds. What I noticed is that the ads broke down into two categories - one where the owner obviously knew the bike, the age, described the components, the size, etc. And the other category was basically, "Litespeed titanium bike. Large" and nothing about anything else. Not knowing anything about a high end, expensive bike suggests you didn't buy it.

Now, do I know for a fact that the "Litespeed titanium bike. Large" was stolen? Of course not. But I know whom I'd buy from.