It started with a group of terrorist snipers in the Hotel Ukraina who fired randomly into a crowd of civilians. None of them were ever prosecuted. The attempt to pin it on the Berkut failed miserably.

One of them was identified by a Ukrainian war hero as Andriy Parubiy, far right nut and future speaker of the rada. Several of them identified themselves as Georgian mercenaries who were hired by Andriy Parubiy.

The goal of the terror attack was clearly to overthrow a democratically elected president that was overwhelmingly popular in Crimea and the donbass and install a puppet who could be relied upon to do the bidding of the west.

This was successful, and is what kicked off the civil war.

Victoria Nuland's phone call where she "picked" the puppet on behalf of the US state department was leaked. You can listen to it.