TL;DR: The wallet held the proceeds of "Silk Road" drug trafficking, a hacker stole the wallet. Feds tracked down the hacker and just made a deal with him to give them keys to the $1B wallet. Hacker prob got a nice pen and stayed out of Federal prison.
> and stayed out of Federal prison. I'm a little confused there, because both the hacking and money laundering should have been beyond the statute of limitations.
So while the hacking and money laundering aren't criminally liable, the coins themselves are proceeds from a criminal enterprise, and if you stand in the way of the government trying to get them you could be hit with obstruction(?).
Realistically regardless of the technical level of criminality I doubt that the FBI would let a billionaire be minted with DNM money.