If you want more hair raising info listen to the this American life podcast episode on putins origin.
https://m.thisamericanlife.org/radio-archives/episode/614/the-other-mr-president
Back when he was politically unknown and Yeltsin was a drunk tottering around he needed to elevate himself and fast. There is evidence he used his ex fsb guys to blow up apartment blocks in the middle of the night, multiple times over a period, killing hundreds of people, with military grade explosives, stuff only state security forces had access to.
He blamed these explosions on Chechnya rebels who by that stage had no reason to bring such attention on themselves. He vowed to crush them and became the law and order candidate. His machismo was built then. Back then his involvement was unthinkable but now with his track record of killings it seems completely in character.