‘Mama” was the only message that 23-year-old Russian student Sofia Sapega managed to get to her mother last Sunday before contact was lost for good after her Ryanair jet was forced to land in Minsk, escorted by a fighter jet.

Several hours after the text arrived, Ms Sapega was in a Belarusian KGB jail, detained with her boyfriend in a brazen capture that has stunned the world.

Her principal crime appears to have been travelling with Roman Protasevich, a 26-year-old dissident blogger accused of helping organise massive pro-democracy protests in Belarus last year.

“We thought Roman might be in trouble,” Ms Sapega’s stepfather Sergei Dudich told reporters. “But to think that Sofia would be in trouble, too... When she was detained, we assumed they were holding her as Roman’s girlfriend and she’d be out soon. Then came the confession.”

A day after Belarusian state media released a disturbing video showing Mr Protasevich sitting at a desk and confessing to having organised “mass riots” in Belarus,  a similar video of Ms Sapega was posted on the same social media account.

In the video, the student, tanned after two weeks in the sun in Greece and dressed in a black leather jacket and jeans, gives her name.

Then she “admits” to having edited the social media channel that has published personal information about Belarusian police officers in retaliation for staggering brutality carried out against protesters last year.

Ms Sapega’s family did not believe a word of it. “We know our daughter well and it wasn’t like her: it’s not her and it’s not her words. She couldn’t have incriminated herself.”

While the fate of Mr Protasevich is expected to mirror that of the dozens of detained activists who have reported physical torture or psychological pressure in Belarus’s secretive prisons, the future of Ms Sapega is less certain on account of her Russian citizenship.

In the Black Sea city of Sochi on Friday night, Russian president Vladimir Putin gave Belarusian president Alexander Lukashenko his backing and dismissed Western outrage.

Mr Lukashenko told Mr Putin: “There is always someone who causes problems for us. You know about them, I’ll inform you.” But under the surface, Mr Putin may be wondering if one of his most reliable allies has gone too rogue this time.

A popular Russian opposition blogger earlier this week launched a petition, urging the Kremlin to bring Ms Sapega home, spurred by a wave of indignation in Russia.

Messages of support for the student have poured in from unusual places: Margarita Simonyan, editor-in-chief of the Kremlin-funded English-language television news network RT, has lambasted Mr Lukashenko for jailing the Russian woman, saying: “Televised confessions don’t do anyone any credit.”

In a recent column in Komsomolskaya Pravda, Russia’s ardently pro-Kremlin tabloid, Alexander Kots expressed concern about the confession video as the Lukashenko regime’s key piece of evidence against Ms Sapega, writing: “Minsk hasn’t produced anything other than a short confession video by the Russian national, and I’m not ready to take their word for it.”

Anna Dudich, Ms Sapega’s mother, is devastated, said her husband, who was also often gasping in distress during the interview. She penned a plea to the Kremlin earlier this week, urging Russian officials to help secure her daughter’s release.

Remarks released by the Kremlin after Mr Putin’s Friday summit made no mention of the Russian prisoner, despite a Kremlin spokesman indicating early this week that she would be released.

“I hope they will realise that she is just a girl,” Mr Dudich said. “She’s just a 23-year-old, and I hope those people won’t shatter her whole life like this.”

Ms Sapega’s lawyer had visited the jail inside the ominous KGB headquarters on the main street of Minsk all week before he was finally allowed to see her on Friday evening.

Alexander Filonovich said the student looked “perky and healthy” and “hasn’t lost her spirits and is hoping for the soonest release”.

The lawyer was told she is suspected of an unspecified criminal office. The actual charges were not even revealed at a court hearing on Friday when the judge dismissed the defence’s appeal against her two-month arrest.

Ms Sapega — described by friends and family as sociable, friendly and interested in art and fashion — was born to Russian parents in the Pacific port city of Vladivostok before moving to Lida, a Belarusian town near the Lithuanian border, where she was raised by her mother Anna (47), and Mr Dudich (42).

Ms Sapega went to university in Lithuanian capital Vilnius, an hour from Lida by bus, and was able to see her parents at weekends before the border shut down because of Covid-19 restrictions.

After a two-week holiday in Crete and Athens the student and her boyfriend were coming back to Lithuania where Ms Sapega was planning to finish her master’s dissertation. © Telegraph Media Group Ltd (2021)

Telegraph Media Group Limited [2021]