Yes, sure. But that's pure theory.

Of course, he might use Tor whenever he can - and thinks of it!

But only one technical malfunction, or only one single user sloppiness - and he has left real footprints.
He created a hell lot of postings and emails and accounts - essentially he has left the traces that will lead back to him.

Most criminals make mistakes, that's how they are caught, anyway.

And: One day he might want to spend the money - which is in a public ledger.