At Cologne airport on Thursday evening, a group of associates of the late Russian opposition leader Alexei Navalny gathered waiting for a plane to arrive from Ankara. On board were 13 people who, until that morning, had been incarcerated in Russian prisons, including three people who had worked as Navalny’s regional coordinators in various Russian cities and been jailed for “extremism”. After a swap in Turkey, they were now free, along with the Wall Street Journal reporter Evan Gershkovich and two other Americans, who were heading back home on a separate plane. As the 13 disembarked from the plane in Cologne, it was a moment of joy. But there was also an undertone of wistfulness and anger over one person who was not on the plane: Navalny. After all, the contours of this deal had been drawn up with him in mind, and then, just when his freedom seemed tantalisingly within grasp, he died – or was murdered – in prison. With the exchange complete, details can now be revealed that show just how close a swap along similar lines but including Navalny appeared to be back in February, after months of careful planning and supposed Kremlin approval. A detailed investigation by the Wall Street Journal into the behind-the-scenes negotiations over the exchange described how its origins lay in a meeting in Geneva between the Russian and US leaders shortly after Joe Biden became president, long before Gershkovich’s arrest. There, Vladimir Putin suggested setting up a special channel to deal with prisoner swaps, an echo of a cold war practice. Biden agreed. Eventually, it led to Russia releasing the basketball player Brittney Griner, caught at a Moscow airport with a small amount of hash oil in what appeared to be a calculated move to take an American hostage. She was swapped for Viktor Bout, one of the world’s most notorious arms dealers, who was held in US custody. Next, Moscow turned its attention to Vadim Krasikov, an assassin who travelled to Germany on a passport that identified him as Vadim Sokolov and shot dead a Chechen exile in a park in 2019. He was arrested while removing his wig and trying to flee the scene. The Kremlin denied any connection and the assassin refused to speak under interrogation. Journalist Christo Grozev cracked the case, identifying him as Krasikov, part of an elite unit of the FSB, the Russian security service. Grozev made a name for himself tracking down Russian spies and assassins, and grew close to Navalny after he uncovered the FSB poisoning squad that had tailed the politician for months before he was poisoned with novichok in 2020. After the attack, Navalny was evacuated to Germany, where he recovered, and then returned to Russia in early 2021. He was immediately arrested and jailed. Grozev became one of the leading advocates for the inclusion of Navalny in a possible prisoner swap, and thought Navalny could hold the key to persuading Germany that it was worthwhile to give up Krasikov, particularly given the chance that a free Navalny might galvanise the fractured Russian opposition. “There were so many issues to this, but to the other side of this equation was Navalny, with an actual plausible chance of him to play a role in the Russian political future in years if not months to come,” said Grozev in a telephone interview with the Guardian on Friday. He began probing the idea with Russian contacts who had been keen to act as intermediaries for a potential swap, but found himself coming up against a brick wall whenever the name Navalny was mentioned. “I worked with at least two former security officials. They were very well positioned to be one handshake removed from Putin. And they all wanted to earn that credit, but the name of Alexei was the fear factor for both of them,” said Grozev. Grozev then asked the US special presidential envoy for hostage negotiations, Roger Carstens, if he might try asking the Russian oligarch Roman Abramovich to raise the issue with Putin, the Journal reported. Abramovich had been active in informal negotiations with Ukraine over a possible peace deal at the beginning of the war, and then in talks over prisoner-of-war swaps with Kyiv, and was already seen as an established conduit to Putin. Carstens raised the issue with Abramovich when both men were in Israel after the 7 October attacks, the newspaper reported. “Abramovich initially said Putin will not agree, then he discouraged Carstens from asking him to pass on the message, but Carstens was very committed to this cause and idea, and knew that nobody else would ask this question, so he begged him to ask. And a few days later Abramovich reported that, surprisingly, he said yes,” said Grozev. A source in Moscow with knowledge of the negotiations confirmed that Putin had approved the deal in, in principle, in autumn. “The Germans didn’t want to give Krasikov up, but then there was a world-famous person, Navalny, who was well known in Germany, and this was something they could sell, and it was a happy joining of circumstances: Putin gets Krasikov, the Germans get Navalny and the Americans get the Americans back,” said the source. With that green light, the pieces began to slide into place. Calls were made to allies in Slovenia and Norway to secure agreement for Russian spies arrested there to be part of the swap. The broadening of the exchange was meant to make the idea of freeing Krasikov more palatable to Berlin. “It always had to be a big enough package in order for no country to take a specific domestic political risk. It had to be fuzzy,” said Grozev. The Wall Street Journal investigation showed that the negotiations remained delicate and fraught, involving multiple players in Washington, Berlin and Moscow. A surprisingly large role was played by Ella Milman, Gershkovich’s mother, who lobbied US officials tirelessly to keep the jailed reporter at the front of their minds. In January, she flew to the World Economic Forum in Davos to meet Wolfgang Schmidt, German chancellor Olaf Scholz’s chief of staff. “You have the key,” she told him. Schmidt promised to help, and the same day, Scholz and Biden spoke on the phone. “For you, I will do this,” Scholz later told Biden, the Journal reported. Eventually, a deal of eight for eight came into view, said Grozev. It would have involved Navalny, Gershkovich and former US marine Paul Whelan among those released by Russia, while a similar group of Russians to that seen this week would return to Moscow. Once everything was lined up, Abramovich went back to Putin for final approval, and again the response was positive. “At an early stage he gave an agreement in principle, and then at the final stage, when it was all ready, he also approved it,” said the source in Moscow. Then came shocking news. The 47-year-old had died, of unexplained causes, in the remote Arctic penal colony where he was being held. “I received confirmation that the negotiations were at their final stage on the evening of February 15,” Navalny associate Maria Pevchikh said earlier this year. “On February 16, Alexei was killed.” In the months after Navalny’s death, gradually a new deal began to take shape that involved more Russian opposition figures and again getting the Germans onside. The result, after months of careful wrangling in numerous capitals, was the exchange that went through on Thursday. Grozev was in Cologne to meet the plane as it landed from Ankara, and said that after Navalny’s death it was hard to weigh whether the exchange, which effectively rewards Putin’s policy of hostage taking, was a good decision. “With Navalny gone, I find it harder to evaluate where the balance lies now,” he said. He spoke to the Guardian by phone while out shopping for clothes for the Russian political prisoners, who had arrived still clad in prison uniforms, and said, despite the doubts, it was still a positive that so many prisoners were now free. “There was a moral imperative to use the accumulated resource and Germany’s willingness under certain conditions to free Krasikov and free as many people as possible,” he said.