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I think that police international investigation is the best chance for you, and no matter how well-hidden hacker traces are - if there is a will and determination the hackers can be found. At the present time even most careful hacker leave some digital footprint, so I'm therefore confident that something will be discovered.

Did you maybe try to get out to the public (except forums) with your story, maybe only to crypto-related media? Maybe someone has a similar experience which can help in the investigation, or you case may serve as a warning to others, in a way to prevent someone else from being the victim in the same way.

I understand regarding monitoring stolen coins, it is good that you give them in public - maybe someone find some trace.