A place in hell might be nice for them, but hey, why can't NATO work together to build a new prison for these criminals? That's kind of a joke - that's not really NATO's role, I don't think.
But seriously, why can't partner nations work together to build a new prison with no access to the Internet for prisoners whatsoever, not even email, and build it where? IDK - think of one of the least corrupt governments you know of and build it there.
Think of it this way: Every DIME they steal from Americans or Canadians or the Brits is money THAT WILL NOT LONGER BE TAXED by their home nations. Therefore, the government is losing out on tax revenue also thanks to these crimes.
So yeah - make it a Federal crime and build another prison for this particular brand of criminal and their accomplices. Or just add a wing to an existing Federal prison.