21/09/30 12:06:16.27 GvuBtalq.net
The United Nations said Mr Shishov's death adds another level to "our worries about what is happening in Belarus", and called for an investigation.
Mr Shishov's death is the latest incident to prompt international scrutiny of President Lukashenko's authoritarian government.
At the Tokyo Olympics, sprinter Krystina Timanovskaya, 24, was granted a humanitarian visa by Poland after refusing her team's order to fly back to Belarus early.
She said she had been forcibly taken to the airport for criticising team 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.
'We were warned repeatedly'
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 and any possible threats to his life.