Jan Marsalek is one of the most wanted individuals on the planet, we managed to find where he fled to, and discovered his unusual collection of passports, and the FSB's long standing interest in his activities bellingcat.com/news/uk-and-eu…
Working with @the_ins_ru and @SPIEGEL_English, we were able to establish Marsalek fled to Belarus, and while we were digging discovered Marsalek had multiple passports, including a diplomatic passport from an unknown country.
Not only that, but after gaining access to the FSB's database tracking persons of interest, we discovered the FSB had not only been tracking his travels to Russia, but unusually to other countries across the world. 
Marsalek was also a frequent visitor to Russia, with 60 visits in the past 10 years, his immigration dossier numbering 597 pages. His last visit on his Austrian passports was in September 2017. It's unknown how much he travelled on his diplomatic passport, issued in 2018.
The FSB interest in Marsalek appears to have started in 2015, when his trips to Russia became more frequent. It's unknown why there was this additional interest, but we've only see it once before, with a financial backer of the Brexit referendum.
More details of the investigation can be found here bellingcat.com/news/uk-and-eu…
