In life or death, Navalny will 'influence history': lawyer
Mikhailova, who is arguably the most high-profile member of Navalny's defence team, had defended the opposition politician for 16 years.
She was often pictured by his side as President Vladimir Putin's top critic sought to clear his name in a years-long legal tug-of-war with the Kremlin.
Now a target of a criminal probe herself, Mikhailova left Russia in October last year and is applying for asylum in France.
"Alexei Navalny is an amazing, courageous, charismatic politician," Mikhailova, who looked visibly upset, said at a Russian opposition event in Paris.
"The authorities claim that he is dead. Even if that is so and he was killed, I am sure that he will not only go down in history but will also influence the future course of history," Mikhailova told several dozen people, her voice sometimes breaking.
She did not take questions and declined to speak to journalists.
Russian authorities said on Friday that Navalny, 47, suddenly died in his Arctic prison. The announcement plunged his supporters around the world into a state of shock.
Speaking at the event organised by the Russie-Libertés association, Mikhailova sometimes spoke of Navalny using the present tense.
"He's not like regular people. He is an iron man," she said.
Navalny barely survived a poisoning with the Soviet-designed nerve agent, Novichok, in 2020. Following treatment in Germany, he returned to Russia in 2021 and was immediately arrested and subsequently jailed.
Mikhailova, 50, said she warned the opposition politician against coming back to Russia.
"In Berlin, I told him, 'You'll be jailed for 10 years," Mikhailova said.
"And he replied with a smile: 'You always say I'll be jailed. Well, you'll be defending me then."
- 'Abused and starved' -
Upon return he was sentenced to two and a half years in prison. Last year a Russian court sentenced him to 19 years behind bars on extremism charges.
Mikhailova said he had been tortured in prison for the past three years but was not broken.
"They abused and starved him," she said.
"He spent about 300 days in a cold punishment cell where he could either stand or sit on a metal stool during the day," Mikhailova said.
"Three times a day a mug of hot water was brought to him and it was the only hot meal he had."
Last fall, the Russian authorities cracked down on Navalny's defence team.
In October, three lawyers defending Navalny were detained and charged with taking part in an "extremist organisation."
Russian authorities have accused Navalny's defence team of spreading his anti-Kremlin message from prison by posting his letters on social media.
The announcement of Navalny's death came as Putin is gearing up to extend his two-decade hold on power in a presidential election in March.
Mikhailova, who says she was on holiday abroad when the three members of the defence team were arrested, decided against returning to Russia where she knew she too would be jailed.
Writing on Facebook in January, she said life abroad was difficult for her daughter and her. "We have no home and a lot of problems," she added.
In mid-February, a Moscow court ordered Mikhailova's arrest in absentia.