As a rule, the unresolved deaths of Russian opposition figures are their deaths in Western Europe or in the U.A.
And these deaths must be resolved by authorities of respective countries, not by Russia.
But, as a rule, authorities of Western European countries and the U.S. never find any culprits.
Or to be more exact, they
say that they haven't found any culprits.
I am sure that most of these deaths have been resolved but it has been found that Russia had nothing to do with these deaths. However, authorities of Western European countries and the U.S.
prefer to pretend to be fools who are incapable to resolve crimes on their own territories.
If somebody is shot dead, burnt alive, stabbed to death etc. on the territory, which is under control of Ukrainian rulers, it is the duty of Ukrainian rulers to find who are the culprits.
But in numerous cases Ukrainian rulers – like authorities of Western European countries and the U.S. – say that they cannot find any culprits.
In my opinion, such cases are too numerous – almost 200 unresolved political murders in the last 8 years (see
here) – for a relatively small Ukraine.