The bulk of the work was done by Christo Grozev, a Bulgarian Bellingcat researcher based in Vienna. He was able to purchase flight records and phone data on the black market, due to Russia’s porous data protection standards, and searched for passengers on flights to the same cities where Navalny travelled, matching them with other data about known operatives. In November, when Navalny was recuperating in the German countryside, Grozev visited to compare FSB travel records with Navalny’s trips. The match-up was striking…

When the pieces of the puzzle began falling into place, Grozev had an enormous rush of adrenaline. “I couldn’t sleep. I just couldn’t believe that the evidence was so clear,” he said in an interview in Vienna. “Usually I have to spend a much longer time assessing and digging, and here there were 34 different flights. There was statistically zero chance this could be a coincidence.”

Since then, he has identified six more trips made by agents from the team tracking Navalny using different aliases, taking the total number of trips in which Navalny had accompanying officers from the FSB team to 40. “Clearly there was no expectation they would ever be discovered. But it’s impossible not to leave traces in today’s world. If you were there, you leave a trace,” said Grozev.