Last Sunday Sofia Sapega and her partner, dissident journalist Roman Protasevich, were detained by Belarusian authorities.
The pair had been travelling on a flight from Athens to Vilnius, in Lithuania, when Belarus scrambled a military jet and forced their plane to land in Minsk – the Belarusian capital.
Western countries have accused Belarus of hijacking the Ryanair plane, which was rerouted over an alleged bomb threat.
Ms Sapega, a Russian citizen, had been travelling to Vilnius to defend her masters thesis at European Humanities University, where she is studying international law.
In a statement, the university said called for the “observance of rights and freedoms” guaranteed in Belarus’s constitution.
Ms Sapega, 23, is being held in a pre-trial detention centre in Minsk for two months “as a preventative measure,” her lawyer Alexander Filanovich told the BBC.
Russia’s foreign ministry said in a statement that she could face criminal charges.
Mr Filanovich says she’s been accused of committing a “criminal offence”, but he was unable to provide more details because of a non-disclosure agreement signed with Belarusian authorities.
The probe is being led by the Investigative Committee of Belarus, a branch of the country’s security service. Mr Filanovich said investigators are compiling information for the Russian consulate, and it was possible this will be shared on Russian state media.
Since the pair’s arrest, a video of Ms Sapega has been released by Belarusian authorities. In it, she says that she edits a Telegram channel – Black Book of Belarus – which publishes the personal information of security officials in the country. Belarus has classified the channel as an extremist group.
Critics suggest that she made the statement under duress.
According to one of her classmates, Sofia had spent most of her life in Belarus and was not an opposition activist.
Ms Sapega’s mother, Anna Dudich, told the BBC that Sofia had not been working in Lithuania for Belarusian opposition leader Svetlana Tikhanovskaya.
Ms Dudich and several of Sofia’s classmates confirmed that she had been based in Vilnius since August 2020, and had not travelled to Minsk to take part in protests against President Alexander Lukashenko.
Before her arrest, Sofia managed to write just one word to her mother on WhatsApp: “Mummy”.
