Negotiations to release Russia’s opposition leader Alexey Navalny in a prisoner swap had reached their “final stage” just before his sudden death, a top aide to Navalny has said.

Navalny and two US citizens were on the verge of being exchanged for Vadim Krasikov, a Russian hitman serving a life sentence in Germany for the 2019 assassination of a former Chechen fighter in Berlin, according to Maria Pevchikh, a top aide to Navalny, speaking in a video published Monday on his YouTube channel.

“Navalny was supposed to be free in the coming days because we had achieved a decision on his exchange,” Pevchikh said. “I received confirmation that negotiations were at the final stage on the evening of February 15.” Navalny was reported dead in an Arctic prison on February 16.

The State Department would not comment on reports of a potential prisoner swap, and spokesperson Matthew Miller would not say whether such a deal would have included the two Americans designated as wrongly detained in Russia: Wall Street Journal reporter Evan Gershkovich and former US Marine Paul Whelan.

Putin had recently signaled his interest in a prisoner exchange with the West involving Krasikov and Gershkovich. He told former Fox News host Tucker Carlson “an agreement can be reached” to release a man whom he said “eliminated a bandit in one of the European capitals” motivated by “patriotic reasons.”

Pevchikh stated that Putin “could have gotten” Krasikov “if he gave up Navalny,” but alleged that, because Putin could not tolerate the thought of Navalny being free, he instead decided to “get rid of the bargaining chip.”

The Kremlin has denied any role in Navalny’s death.

“It’s absolutely illogical, absolutely irrational, it’s the behavior of the mad mafioso. But the point is that Putin has gone mad with hatred for Navalny. Putin hates him so much that he acts to his own detriment and against his own rational interests,” Pevchikh said.

Russia’s prison service claims Navalny “felt unwell after a walk” and “almost immediately” lost consciousness while detained in the “Polar Wolf” penal colony in Siberia. It said it was investigating his “sudden death.”

Navalny’s mother, Lyudmila Navalnaya, said last week she had signed his medical death certificate, which said he died of natural causes.

Pevchikh said Navalny’s team had been working on the deal since Russia’s full-scale invasion of Ukraine began two years ago, and accused Western officials of failing to show enough desire or political will to secure his exchange.

“Officials, American and German, nodded understandingly, talked about how important it was to help Navalny and political prisoners, shook hands, promised, and did nothing,” she said.

She said Navalny’s team took desperate measures to free him, even contacting former US secretary of state Henry Kissinger, whom Pevchikh described as a friend of Putin. Kissinger has since died.

Navalny joined a long list of Russian dissidents who died after challenging Putin’s legitimacy. His death comes shortly before Russia’s presidential election scheduled for March 15-17, which is widely seen by the international community as little more than a formality that will secure Putin a fifth term in power and extend his rule until at least 2030.

Navalny’s body was returned to his mother on Saturday, more than a week after his death. Navalnaya had previously claimed Russian authorities were blackmailing her by refusing to hand over her son’s body until she agreed to conditions for “where, when and how Alexey should be buried.”

Peskov said Monday that Navalnaya’s accusations were “absurd” and that the Kremlin “has nothing to do with the case” and therefore “cannot exert pressure.”

Kira Yarmysh, Navalny’s spokesperson, said on Monday his team is “looking for a hall for a public farewell to Alexey” to be held at the end of this week.