I believe they "started" with claiming that statements that the they were about to invade Ukraine were absurd lies, followed shortly later with claims they would control the entire country in three days along with some maps that included Moldova, followed shortly thereafter with lots of nuclear saber rattling when things started going south.

There have also been dozens of assassination attempts against Ukraine's civilian and military leadership, and against Russia's as well, some of which have been successful. The fact that most attempts don't work out doesn't mean it's not happening.