Great work by Bellingcat on Novichok poisoning
It really is impressive the level of information that you can get from OSINT. Some outstanding investigative journalism by Eliot Higgins/Brown Moses. Strongly encouraged to have a read - https://www.bellingcat.com/news/uk-and-europe/2020/10/23/russias-clandestine-chemical-weapons-programme-and-the-grus-unit-21955/