I’d say Poland wouldn’t be capable of this. I mean, you’ve got to be really really really confident that it won’t be public knowledge you’ve done this. And I’d be worried to what extent my intelligence services had been infiltrated if I hadn’t done this type of intervention a dozen times before and gotten away with it.

The same logic leads me to conclude it’s one of the major powers, a country that regularly does major ops and gets away with it. One that wouldn’t be worried about being caught because they hadn’t been caught before.

So: Russia, US, China, Israel, U.K. would be contenders