If we were paying attention, I would say 1999. That was when the FSB bombed apartment buildings in Russia, which Putin blamed on Chechens, which they used as a pretext to retake Chechnya and flatten Grozny. This propelled him into the Presidency, starting his rise as a Tsar in all but name.
I admit at the time I bought the Russian stories about Islamic terrorism, etc. It wasn’t for a few years later when journalists, activists and former FSB agents started getting whacked did I readjust my outlook.