Sergey Fedotov

Britain and Bulgaria are jointly investigating the 2015 poisoning of a Bulgarian arms dealer to determine whether it involved novichok, the nerve agent used in the poisoning of Russian double-agent Sergei Skripal and his daughter, Yulia, in Salisbury last year, the Guardian writes. 

A possible third Russian suspect linked to the poisoning of a former spy in Salisbury flew back to Moscow via a European city a few days after the attack, an investigative website has claimed.