Putin administration's critic poisoned

It is mostly interesting to me to see the whole thing unfolding, because there's basically no doubt that he was poisoned. You just don't ingest that kind of radioactive material in that amount by accident, and I'm just venturing a guess, but I bet it's not readily available to your average joe on the streets. What remains to be seen now is 1) who did it and/or were they good enough at what they do to cover their tracks, and 2) why did they do it. It seems the most obvious that Putin or someone close to him would be involved because the guy was such an outspoken critic, but it seems like he was still involved in some pretty interesting issues - it would make for a nice cover if it was someone altogether different. Either way, I'm interested to see how it ends up.

Jam it back in, in the dark.