Is Russia cleaning house?

Many 'mysterious' deaths have surrounded Russia recently, first a reporter, then a ex-KGB agent and now an ex-Prime Minister. All of which are still under investigation, it does seem odd that all of the people suddenly dying are in some way criticizing the current administration, all of which under circumstances that are hard to explain. The only death that brought showed anything of substance was the attack on the ex-KGB agent after who's death the British government initiated a investigation which now had lead to certain airplanes that fly Moscow London, routes. These events show a very disturbing picture if the Russian government indeed is responsible this means that once more the Russian government restricts speech (was known before) and freedoms and even human rights such as the right to life at will. It would almost seem that the Kremlin is cleaning house with its critics until their either disappeared in fear or dead.

Articles that deal with these events
Russian ex-PM has mystery illness (BBC)
BA passengers in radiation alert (BBC)
Russia (Paladin101)
Spy inquiry hunts further radiation (Al Jazeera)