So sorry about your loss but if truth is to be told, I do not think there's any agency responsible for tracking lost bitcoin, in as much as those coins has left your wallet, you should consider that as your own loss and learn from those mistakes.

I would have said you try reposting them to the law enforcement like the police, but in most cases, after scamming someone, the tend to abandon the contacts used to avoid tracking. You could try your luck though, the may not have changed anything.