The head of a Belarusian non-governmental organization, who had been reported missing on Monday when he went on his morning run, was found dead.
"Belarusian citizen Vitaly Shishov, who had gone missing in Kyiv yesterday, was today found hanged in one of the Kiev parks, not far from where he lived," police said in a statement.
A murder probe has been opened, authorities said, adding that they would pursue all leads including a possible "murder disguised as a suicide."
Shishov heads the Kyiv-based Belarusian House in Ukraine (BDU), an organization that helps Belarusians trying to flee persecution. The organization helps them find accommodation, employment, and legal services.
Police authorities said he was reported missing by his partner when he did not return from his morning run and was not responding to calls on his cellphone.
Human rights organization Vyasna said his Shishov's friends said he had been followed by "strangers" recently, while jogging.
Ukraine, like Poland and Lithuania, has become a haven for Belarusians, following a crackdown on dissent in their home country by President Alexander Lukashenko.
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Belarus has seen mass protests against President Alexander Lukashenko after disputed elections last year. Amid crackdown on dissent, many Belarusians have fled to nearby countries such as Ukraine, Poland and Lithuania.
Belarusian sprinter Krystsina Tsimanouskaya was recently denied participation in the Tokyo Olympics and threatened with forced repatriation after she criticized her athletics federation on social media. She has been granted a humanitarian visa by Poland.
Lukashenko and his son have been banned from Olympic events for targeting athletes who have openly expressed opposing political views.