The opposite of speculation against one individual isn't speculation against another. I don't want to give the impression that I care about this more than I do, but it seems clear to me that someone with the genuine principled opposition to speculation that your last sentence implies wouldn't engage in it at all - and that includes repeating others' accusations against one particular individual, and titling a thread after same. Why not just be honest and admit that your issue is that Putin wasn't included in Peter's speculation?
(I have no idea who killed Mr Litivenko, btw) ******************* There is a big difference between a definite conclusion that Mr. Putin was or was not involved, facts as we now know them, and speculation that he was or was not involved. What I was reading previously was analysis and a conclusion on a murder investigation in the UK that was just beginning . Qui bono from a conclusion that is not substantiated? You decide.
As for the above, the three articles I posted did not state Putin did it or so and so did it--conclusively. Neither did they speculate but as news articles purportedly do they reported the facts as we now know it. If you would like to interpret these reports or headlines as speculation that is you choice. If as I do I interpret these articles as facts as we now know them, that is also reasonable or at least debatable. However. I think it should be quite clear from what I wrote that I do not know who killed him, like you. That said, I do object to Mr. Putin not being considered as a suspect. That does not mean I think he or part of his government did or did not do it. We will see.