One of two men believed by British intelligence to have poisoned a Russian spy’s tea with a rare radioactive substance in London has died, according to a state-owned news agencyOne of the men accused of killing former Russian spy Alexander Litvinenko in London has died of Covid-19 in Moscow, according to reports. Dmitri Kovtun was one of two men who a UK inquiry ruled had poisoned Litvinenko’s tea with a rare radioactive substance back in 2006. Reports from state-owned Russian news agency Tass said Kovtun contracted coronavirus before dying in a Moscow hospital. Kovtun, along with Andrei Lugovoi, was...