You assume something (you don't have solid evidence), and even if you have detailed information, and if your hacker is really in Russia, the chances of launching an investigation or arrest would be minimal - because it's Russia after all.
One of the golden rules when it comes to cryptocurrencies is that the backup is not stored online, and you not only did just that, but you let someone hack your email. You paid dearly for your mistake, but unless you have someone in high politics, the secret services, or something like that - I don't think anyone can help you with this. Maybe try to find a lawyer to help you pro bono, even though you literally grab very thin straws in whichever direction you go.