Long Johns, Forensics and a Bound Russian Killer: Inside the Big Prisoner Swap

The private jet that took off from southwest Germany on Thursday afternoon was carrying a group that may have never expected to be confined together: police officers, doctors, intelligence agents, a senior aide to Germany’s chancellor — and a convicted Russian assassin.

In the back of the plane, the assassin, Vadim Krasikov, sat with his hands and feet bound and wearing a helmet that covered his face; he was not heard uttering a word on the entire flight.

At the same time, a Russian government jet was also headed for Ankara, Turkey’s capital, carrying officers from the F.S.B. intelligence agency and 16 prisoners being released by Russia and Belarus. At one point, one of the F.S.B. escorts made what seemed like a bad joke to the two best-known Russian dissidents on board: “Don’t have too much fun out there, because Krasikov could come back for you.”

This account of the tense hours surrounding the exchange — the biggest between Moscow and the West since the Cold War — is based on new details revealed by Western government officials involved in the process, and on early testimony from the Russian political prisoners released as part of the deal.

The swap freed Mr. Krasikov, the American journalist Evan Gershkovich and 22 others in a complex seven-country deal that required intricate planning and timing. The successful transfer highlighted the ability of some of the world’s most powerful intelligence agencies to cooperate on a distinct operation of shared interest, even as Russia and the West engage in a tense standoff over the war in Ukraine.