Investigating the Navalny Poisoning
Bellingcat has investigated the near-fatal poisoning of Alexey Navalny by the Russian FSB back in August. The details display some impressive traffic analysis. Navalny got a confession out of one of the poisoners, displaying some masterful social engineering.
Lots of interesting opsec details in all of this.
EDITED TO ADD (1/13) Bellingcat on their methodology.