Legal advise regarding a professional SWINDLER

Hi there. I've been cheated out of 500k HKS by a friend/turned out to be swindler. Later found I wasn't the only one, at least 8 others were cheated by him. He'd pretend having financial trouble with his company needing a short bridge loan. We know for sure he swindled at least HKS 14 million from friends and family possibly more. He has several court cases running with companies he seems to have swindled out of 'consultancy fees'.
One of the victims stole his car, after which he left Hong Kong (early Aug).
Since then he's been promising to return the money, however the money never arrives.

Together with 4 victims we decided to report to the police. The main objective being to ensure that the bastard will be arrested the moment he comes back to Hong Kong (whether 3 months or 3 years from now). Getting him convicted is something we're not even interested at this moment; we just wanna make sure that he will get caught the moment he lands in Hong Kong.

Well, that proves quite a challenge. Basically we were told by the police that our case will be treated as a personal dispute over money, not swindling. Even if we'd get 8 victims together, not much chance. I can't believe this!

Furthermore; together we have 6 cheques that bounced. Even that doesn't suffice, we were told.
The officer is only willing to transfer our case to the CIB (Criminal Intelligence Bureau) if we can proof that the cheques were issued after the bank account had been closed.

Does anyone have any advise? With 4 victims reporting together this case shouldn't be treated as a personal money dispute, right? Furthermore, bounced cheques is by itself already an offence. Was the police officer wrong?
Or maybe just better send in the Bulgarians? :)