That's a tough question, because Putin is taking this very personally. Putin, apparently, really feels very personally offended by the fact that Mr. Navalny dared to survive the poisoning; dared to investigate his own poisoning; dared to return to Russia after being poisoned; and, of course, dared to launch this investigation about Putin's luxury palace on the northern seashore. This exposed all this way of thinking that, for Putin, really, money, gold-thread carpets are the most important things in the world. This exposition was very dangerous for Putin, actually. It also exposed that Putin really cares very much about money. Our short answer is to sanction his close friends, his oligarchs, the holders of his assets.
On May 6th, 2021. See this statement in context.