It appears somebody or some group is killing off Russia’s oligarchs. The latest supposedly fell out of a window. The list of those who’ve died is relatively long, and the deaths mostly sound suspicious.
Those are deaths of the people with sufficient resources and clout to potentially challenge Putin, if the public mood should ever seem to make that feasible. A failure to succeed in Ukraine could be the trigger.
If you ask who had means, motive, and opportunity to terminate this entire group, you find the list is quite short. It turns out Russia isn’t a safe place to be visibly wealthy.