An assassin, a Putin foe's death, secret talks: How a sweeping US-Russia prisoner swap came together

The 24-person blockbuster prison swap carried out this week required the U.S. to regroup after the unexpected death in February of Russian opposition leader Alexei Navalny, who’d been seen as a key cog in a potential exchange. It depended on the willingness of Germany to release from custody a Russian who just five years earlier had committed a cold-blooded killing on its soil, and for other European countries to give up their prisoners. And it forced Russia to part with Americans, including Wall Street Journal reporter Evan Gershkovich, it had stockpiled as trade bait.