Vitaly Shishov, an activist who co-found the Belarusian House, an organisation that helps his fellow countrymen fleeing Lukashenko’s regime, was found dead in a park near his home in Kyiv early on Tuesday, a day after he was reported missing, Ukrainian police reported.
Police said they had launched a criminal case for suspected murder but would investigate all possibilities including murder disguised as suicide.
Ukraine, Poland and Lithuania have become havens for Belarusians during a crackdown by President Alexander Lukashenko following a disputed election last year.
The Belarusian House in Ukraine (BDU) helps Belarusians who fled their home country find accommodation, jobs and legal advice. Its activists claim that Mr Shishov was murdered by the Minsk authorities as he was perceived as “a Belarusian dangerous to the establishment”.
“We will fight for the truth about Vitaly's death!,” wrote the Belarusian House on the Telegram website.
BDU added that the deceased had been followed before and the police were informed about it.
"We were also often warned by both local sources and our people in Belarus about various provocations, including kidnappings and liquidations,” the organisation stated.
As another wave of crackdown on the people opposing the regime in Minsk, Belarusian authorities have characterised anti-government protesters as criminals or violent revolutionaries backed by the West, and described the actions of law enforcement agencies as adequate and necessary.