For more than 20 years, Aliaksei Aliakseichyk has worked as a transplant physician at the National Scientific and Practical Center for Children's Oncology and Hematology. He has performed numerous bone marrow transplant operations and is considered one of the Center's top specialists. He was accused of 'calling for restrictive measures (sanctions) or other actions aimed at harming the national security of Belarus' (Part 3 of Article 361 of the Criminal Code).

In 2020, the Center's employees openly spoke out against the violence on the part of law enforcers. As a result, in November 2020, the director of the Center Natallia Kanaplia was fired, after which several more employees were detained, including Aliaksei Aliakseichyk.

On February 16, 2023, the Viciebsk Regional Court found Aliakseichyk guilty and sentenced him to two years and six months of imprisonment in a general-security penal colony. The case was heard by Judge Yauhen Burunou.