This is stated in the final report into the death of Alexander Litvinenko, Censor.NET reports citing BBC.
It's probable that Lugovoi poisoned Litvinenko under direction from the FSB and with the approval of Patrushev and Putin, the report notes.
According to the report, Mr Lugovoi and Mr Kovtun placed the polonium-210 in the teapot to poison Litvinenko, while the first attempt at polonium poisoning had been made on Oct. 16, 2006.
Lugovoi and Kovtun knew they were using a deadly poison, rather than a sleeping pill or truth serum, the inquiry concludes.
Judge Robert Owen led the inquiry in January 2015.
The main conclusions made by Sir Robert Owen are as follows: Litvinenko died after taking a dose of polonium-210 in the amount of 4.4 GBq added in his tea in Millennium hotel bar on Nov. 1, 2006. He neither did it by accident nor committed suicide. It was a deliberate poisoning.
"Of course, I am very pleased that the words spoken by my husband on his deathbed, accusing Mr Putin of his murder, were proved in an English court in compliance with the highest standards of independence and impartiality," Alexander Litvinenko's widow Marina commented on the inquiry.
"I call for the immediate expulsion from the Great Britain of all Russian intelligence operatives working for the FSB (who killed Sasha) or other Russian agencies based in the embassy in London," Marina's statement reads.
Son of Alexander Litvinenko Anatoliy [left in the above photo - ed.] said that in his opinion the murderers of his father were covered up by the Russian state.
"It was a very difficult crime involving a sophisticated murder weapon, - he said in an interview with Sky News. - The killers were under protection of the Russian state. It's always been clear this will be a slow and difficult case."