"Last year's assassination of the opposition politician Boris Nemtsov, however, clearly beyond Putin's limits. Could Putin have said something about Nemtsov that someone could have taken as a go-ahead to kill him? That seems impossible to me. I have never heard anything like that from Putin, even with regard to people he hates. Putin sometimes mocked Nemtsov a bit, but he tolerated him. After the assassination, Putin disappeared for a few days -- apparently, what had happened was to unexpected."
Excerto do artigo "Russian Politics Under Putin" de Gleb Pavlovksy/Foregin Affairs (Maio/Junho de 2016).