Sorry, is it the same Karpov who's being sanctioned for SUPPORTING Putin? Are you counting every trauma in Russia as "critic of the war"?

Yegor Prosvirning as a critic of the war? ... well, maybe. He criticized Putin for starting too small war too late; according to what I know from people who knew him personally, he could be on drugs.

Dan Rapoport died in USA; ask Washington Police what do they think on case. A hint: should there be a slightest evidence of possible intervention from Russia, you'd hear it.

Marina Yankina was not a critic of the war, put she held high rank in MD finance. I'd suppose she was cornered by possible criminal investigation.

Ravil Maganov... okay, that's possible, but pure financial affairs are at least as likely as political.

But, of course, there could be something like

https://en.wikipedia.org/wiki/Larry_Ford

https://en.wikipedia.org/wiki/David_Kelly_(weapons_expert)

https://www.bbc.com/news/uk-england-wiltshire-24457389

Life's complex.