https://www.kommersant.ru/doc/3811568
https://www.kommersant.ru/doc/3804857
https://www.bbc.com/russian/features-46344074
http://expert.ru/siberia/2018/48/usilit-eksport-uglubit-pererabotku/
http://expert.ru/ural/2018/48/ot-bankrotstva-k-natsionalizatsii/
http://www.ng.ru/week/2018-11-25/8_7447_politics.html
“Natural causes” can’t be ruled out. But those include stress, and there’s no doubt Gen. Korobov of the G(R)U was under a lot of that.
https://www.thedailybeast.com/inside-the-mystery-of-the-dead-russian-spy-chief
https://www.kommersant.ru/doc/3807374
https://www.bbc.com/russian/features-46291929
https://www.gazeta.ru/politics/2018/11/23_a_12069265.shtml