It shouldn't be too difficult to follow the bread crumbs, and find this guy.
Let's assume he has access to the "WTB" forums, and the site as a whole.
If he/she is a semi bright individual then Tor would be the browser used to view here (or a vpn).
Point is... IF there is any logging done on this site it would be easy to narrow down who viewed your WTB post. I'd look for Tor first. Meaning a single user that has a different IP address or country of origin every time they logged on.
At least it's a beginning.
The Gmail account is also a bread crumb. Usually a DOB is the numbers. At least for most people.
Being he/she used the 'net" to commit this fraud... it's a federal offense.
Yes I know... The assumption is there are bigger fish to fry but who knows. This person is most likely a life long (1/05/74 ?? ) criminal, and may have enough skeletons to be worth looking into.