[Mac1]

"Only if proven."

I think the chances of proving something like this has never been greater; also: using an extremely rare, hard to manufacture substance for triggering atom bombs (first used in the Nagasaki bomb, if not Trinity) kind of draws attention that you wouldn't want especially if you were interested in foreign investment/Western style economy/avoiding the impression of a murderous, totalitarian state.

[alecqss]

I think that chances of proving are nil.

As for the image/investment issue, I believe, it has nothing to do with this. Whether West decides to get tougher with Putin or not will not depend on murdered dissident here or murdered journalist there (unless, again, Putin's complicity is proven. Then embarrassment will force some actions even if West does not desire complications).

It does not matter, in the end, how your image initially suffered. If the West decides not to confront Putin and if case is not proven, then image will recover in no time and the whole affair will be forgotten.

In meantime, one dissident with pesky investigative habits is silenced and his allies are put on notice.

On the other hand, if Putin's foreign and economic policy will prove to be to much for the west, it will not make any difference for the Russia's and Putin's image whether dissidents are killed with poison, bullet, whether high-profile or low-profile murder was. Soviets image was tarnished well before they killed that Bulgarian dissident...