There are only a handful of countries that won't accept the US arrest warrants and turn over whoever. A few countries will demand something first, but this means no death penalty, not something that is in anyway a big deal for the other country. It is semi-routine for most countries to capture and turn over criminals within the borders to another country.
That is why people bring up Russia and North Korea. Those are the two most likely countries that wouldn't. There are a few others, but not many.
Even China which in general I wouldn't trust would in this case. If China did an attack like this it would be much more targeted and they wouldn't be looking for ransom money - See the attacks on the Iran nuclear program for example: attack a target that actually matters. (those attacks were probably US or Israel, but it is the type of thing China might do).
That is why people bring up Russia and North Korea. Those are the two most likely countries that wouldn't. There are a few others, but not many.
Even China which in general I wouldn't trust would in this case. If China did an attack like this it would be much more targeted and they wouldn't be looking for ransom money - See the attacks on the Iran nuclear program for example: attack a target that actually matters. (those attacks were probably US or Israel, but it is the type of thing China might do).