By Laura Gozzi and Vitaly Shevchenko
Navalny was arrested in January 2021 and was serving a 19 year sentence. Photo: Handout / Moscow City Court press service / AFP
Alexei Navalny was about to be freed in a prisoner swap when he died, according to his colleague Maria Pevchikh.
She said the Russian opposition leader was going to be exchanged for Vadim Krasikov, a Russian hitman who is serving a life sentence for murder in Germany.
Two US citizens currently held in Russia were also going to be part of the deal, Pevchikh claimed.
She claimed negotiations were at their final stage on 15 February.
BBC News has not seen any evidence for the claims and is unable to independently verify them.
Navalny died on 16 February in his cell in the prison colony in Siberia where he was being held on a 19-year sentence over charges that were widely seen as politically motivated.
Prison officials said the 47-year-old had fallen ill following a walk.
In a video posted on Navalny's YouTube channel, Pevchikh, who is the chairwoman of his Anti-Corruption Foundation (FBK), claimed negotiations for a prisoner swap had been under way for two years.
She added that, after the start of Russia's full-scale invasion of Ukraine in February 2022, "it was clear that Putin would stop at nothing" and that Navalny "had to be freed from jail at any cost, and urgently".
According to Pevchikh, Navalny was going to be freed under a humanitarian exchange and US and German officials were involved in the talks.
A spokesman for the German government said on Monday they were aware of reports on a planned prisoner swap, but refused to comment further.
Pevchikh said a plan for the prisoner swap was finally reached in December,
She said Vadim Krasikov - a Russian who was found guilty of shooting former Chechen rebel commander Zelimkhan Khangoshvili in the head at close range in Germany in 2019 - was going to be part of the deal.
Two US nationals currently held in Russia were also going to be exchanged, Pevchikh said.
Several US nationals are currently being held in Russian jails, and Pevchikh did not specify who would have been part of the alleged swap.
Earlier in February, Russian President Vladimir Putin told US host Tucker Carlson that talks were ongoing with the US about freeing American journalist Evan Gershkovich, who is being held on espionage charges.
Putin hinted that, in exchange, Russia would accept a person who "due to patriotic sentiments, eliminated a bandit in one of the European capitals… during the events in the Caucasus" - almost certainly a reference to Krasikov.
Pevchikh claimed Putin changed his mind about the deal at the last minute.
She said he "could not tolerate Navalny being free" - and since there was an agreement "in principle" for Krasikov's release, Putin decided to "just get rid of the bargaining chip" and "offer someone else when the time comes".
"Putin has gone mad with hatred for Navalny," Pevchikh said. "He knows Navalny could've defeated him."
It is unclear why Putin might have agreed to swapping Navalny for other prisoners.
The Kremlin has not yet reacted to the claims put forward by Pevchikh.
Putin's spokesman Dmitry Peskov has previously said allegations of government involvement into Navalny's death were "absurd".
Authorities initially refused to hand Navalny's body over to his mother, only relenting eight days after his death.
Navalny's widow, Yulia, has said he was killed on the orders of Putin. The Kremlin has denied these allegations, calling Western reaction to the death "hysterical".
On Monday, Navalny's spokeswoman Kira Yarmish posted a message on social media saying his allies were looking for a venue where supporters could hold a public farewell later this week.
Such an event is expected to be closely monitored by the authorities, provided it is allowed to go ahead at all.
A rights group said 400 Russians were arrested across the country for laying flower tributes to Navalny following his death.
- This story was first published by the BBC