The Russian parliament fast-tracked a law against "fake news" at the end of March amid the Covid-19 pandemic. The legislation introduces criminal proceedings for the authors of false information published in the media and is backed up by an artificial intelligence system as well as an army of cyber activists who are tasked with trawling through the web. But Russian civil society groups say the law is an attack on civil liberties and that its real function is to silence dissident voices critical of the authorities' handling of the health crisis. Our correspondents report.