The early reports on poisoning were questioned initially due to the source. The bloke is around so could have been interviewed? 2 Ukrainians as well.
A new type of news source is being mentioned now - open source. Not clear what it means other than it seems to be not verified.
The bloke himself. He has been a Russian MP equivalent.

Boris meets some of his MP's personally. His opportunity style richness could be down to a number of things especially when Putin and his predecessor were determined to get shut of communism. All reports say this period did improved Russian living standards. The bits he was associated with did increase output. He was a trader previously so would understand the industries to some extent. Suppose like most things - depends how it's all looked at. He has spent money charity style in Russia and but less in Israel. Selling Chelsea - reports say he doesn't want the proceeds they can go to charity.
Russia as with Ukraine is said to be corrupt. How corrupt - I don't know but business in that sort of atmosphere is likely to involve bribes as it did not long ago on a UK arms sale. There are lots of countries about with that problem. Ukraine has it's oly's too.
Must admit given what I have read I'm inclined to think he is a better example of the breed. He is well down the world rich list now and it wouldn't surprise me if some who have done better are in the west. Nothing to do with current sanctions.
Autocratic despots? Well Israel met with 1/2 dozen of those recently along with Blinken. I've no idea how many options appear on Russian voting slips.
Do you think money doesn't influence politics everywhere? Afraid I do. Popularist aspects do too. I have heard that Russians like Putin because the west doesn't like them so they need a strong leader. That straight from a bloke in Russia when I visited.