In recent messages talked with me as if we had never communicated before.But we had a lot of disputes and communication. Anyone for whom the native language is Russian will notice changes in the style of writing messages.
If you are to bring up such a case, then providing evidence is also necessary instead of just speculating. For example, how your communication with him changed over time. Seeing what Symmetrick did over the past few weeks, I got convinced that his way of thinking was somewhat immature or kiddish. Maybe he "immaturely" started ignoring you and pretending he doesn't know you because his ego is still hurt after being exposed.He has also changed mail but so far if he could sign transaction from old wallets, we cannot say that hands are changed just by speculating writing style.
What if he transferred the ownership of private keys too? 