Kremlin critic Yuri Felshtinsky told Newsweek: "In the eyes of the Russian government, he committed treason"
Convicted Russian spy Sergei Skripal's "substance exposure" is drawing comparisons to the 2006 death of Russian intelligence agent Alexander Litvinenko's acute radiation poisoning.
A Russian protest group is challenging its country's right to host the 2018 FIFA World Cup.
Litvinenko was poisoned in London in 2006.
Yuri Shvets testified yesterday as part of the inquiry into former Russian intelligent agent Alexander Litvinenko's death.
The public inquiry into Alexander Litvinenko's death takes place nine years after the former KGB spy died after drinking poisoned tea in London.