How does above info prove that LAngle specifically exploited or cheated the particular game ? Your explanation mergly proves that he had multiple accounts on your casino and was also active on other casino's, nothing much.
They do not necessarily need to prove this particular game was cheated. Having multiple accounts on their platform is against their Terms of Service, more so when you have cheated them on your previous account(s), that doesn't really count as 'nothing much', as all future accounts would be restricted.
Someone wanted for a crime can be arrested while doing something completely legal.This kind of plateform are the reason why a lot of people are scared about cryptocurrencies. A cheater can take your money
Scams like this can also and have been run using fiat currencies. And with Fiat currencies the connection that was established between both accounts using the blockchain will take lots of time, paper work and approval to be checked as the blockchain is much more transparent.