I'm just analyzing. Who was interested in Politkovskaya's murder? Russia? Putin? Why do Politkovskaya was killed on Putin's birthday? Why do Litvinenko was poisoned in theatrical manner?

The answer is simple. Just because America was interested in their death. You ask why? The main reason was to not let Europe cooperate with Russia and to unite Europe against Russia.

In 2001-2005 Putin worked hard to cooperate Russia with Europe. USA do not want to let Europe to cooperate with Russia. That's why that hysteria about "totalitarian Putin's regime" appeared in western press and such persons like Politkovskaya and Litvinenko were killed.

Read Emmanuel Todd - Apres l'empire, Essai sur la decomposition du systeme americain. He wrote well about that. His book was written in 2002, but he foretold that America will do some provocations against Russia and increase pressure on Russia to not let Europe cooperate with Russia.

Because if Europe will cooperate with Russia, there will be no need in America as empire.