The head of a group helping people who have fled Belarus has been found dead near his home in neighbouring Ukraine.
Vitaly Shishov's body was found hanged in a park in Kyiv, a day after he failed to return from a jog. Police have opened a murder inquiry.
Police said they were investigating whether he had been killed and his death made to look like suicide.
Mr Shishov led the Belarusian House in Ukraine, helping people who left Belarus amid a police crackdown.
Ukraine, Poland and Lithuania - neighbours of Belarus - are the main destinations for those fleeing persecution, following the disputed re-election of President Alexander Lukashenko in August 2020.
Friends of Mr Shishov reported that he had been followed recently, Belarusian journalist Tadeusz Gizcan said in a tweet on Monday.
The Belarusian House in Ukraine provides support to new arrivals in finding accommodation, jobs and legal advice, its website says.
Meanwhile a Belarusian athlete competing in the Tokyo Olympics was granted a humanitarian visa by Poland after refusing her team's order to fly home early.
Sprinter Krystina Timanovskaya, 24, said she had been forcibly taken to the airport for criticising coaches, and voiced fears for her safety.
Earlier this year, there was an international outcry over the detention of opposition Belarusian journalist Roman Protasevich and his girlfriend, after the Ryanair plane they were travelling on was forced to divert and land in Belarus.
Police said that they had recovered Mr Shishov's mobile phone and personal items from the scene.
They are asking anyone who knew him to get in touch with any information about the last few weeks of his life, about his state of mind and also any possible threats to his life.
Mr Shishov left his home on Monday morning and it was assumed he had gone for his daily jog as his running gear was not found there later, colleagues at the Belarusian House in Ukraine (BHU) said.
He made several calls from his phone but hung up each time they were answered, they added.
His colleagues conducted their own search of the woods where he usually went running.
One colleague, Yuri Shchuchko, told Current Time TV that police said Mr Shishov had marks on his face, suggesting that he had been beaten up.
Mr Shchuchko said Ukrainian security service officers and police had privately warned the BHU about threats to activists.
"They said we should watch ourselves because a Belarusian KGB [secret police] network was active here and anything was possible," Mr Shchuchko said.
The BHU said in a statement: "We were warned repeatedly by local sources and our people in Belarus about possible provocations, going as far as kidnapping and assassination. Vitaly reacted to those warnings with stoicism and humour."
BSDT: 1625 HRS, AUG 3, 2021