Sergei was detained on September 30, 2021, initially for a comment he made following the deaths of State Security Committee (KGB) officer Dmitry Fedosyuk and IT specialist Andrei Zeltser in Minsk. He was summoned to the military registration and enlistment office, where security forces were already waiting. His home was later searched in his absence.
In early September 2022, it became known that the State Security Committee had added Sergei to the "list of persons involved in terrorist activity." In November of that year, he was sentenced to imprisonment in a maximum-security penal colony.
As a result of the appeal, the prison term was reduced from 6.5 years to 6 years.
On September 16, 2026, he was released after a visit to Minsk by US President Donald Trump's special representative, John Cole, and taken to Lithuania.
