If you strongly believe that this user is scammer, create a flag and ask the community to support you
https://bitcointalk.org/index.php?board=83.0.
Scammer will get big warning like this:
Warning: One or more bitcointalk.org users have reported that they strongly believe that the creator of this topic is a scammer. (Check their trust page to see the detailed trust ratings.) While the bitcointalk.org administration does not verify such claims, you should proceed with extreme caution.
If you are scammed you after that then you are an idiot.
next problem becomes verification of scam before it happens, which is 100% unconfirmed, and scammers will create more accounts.