North Korea might. Silk Road went under due to attempting to hire one.
The more likely concern is that someone will sell you out to any of the numerous governments who feel you wronged them. Leading to decades of life in prison.
I wouldn't expect there to be documented cases yet. The hypothetical case in question is a hacker taking hundreds of millions of dollars, not being caught initially, but then being caught years later. Crypto as a whole is just 15 years old, and it's only really been hot for under a decade. There have only been a handful of cases with such large dollar amounts, and most occurred in the last 5 years. And I expect most of the people who pull this off will be properly paranoid.
These chains are created by startups with VC money, they are not going to hire hitmans.