Dmitry Kovtun was accused of poisoning former Russian spy Alexander Litvinenko in London with a rare radioactive substance hidden in his tea in 2006

One of the men accused of killing former Russian spy Alexander Litvinenko in London has died of Covid-19 in Moscow, it has been widely reported.

Dmitry Kovtun was one of two men who, according to a British investigation, had poisoned Mr Litvinenko’s tea with a rare radioactive substance in 2006.

In reports attributed to Russian news agency Tass, Mr Kovtun is said to have contracted coronavirus before dying in a Moscow hospital.

Mr Kovtun, along with Andrei Lugovoi, have been accused of being behind the murder of Mr Litvinenko 16 years ago at the Millennium Hotel in Mayfair.

According to reports, Tass quoted Mr Lugovoi, now a member of Russia’s parliament, as saying he was mourning the death of a “close and faithful friend”.

A British public inquiry concluded in 2016 that the murder of outspoken critic of Vladimir Putin, who died after drinking tea containing radioactive polonium-210, was “probably” committed with the approval of the Russian president.

Led by former High Court judge Sir Robert Owen, the inquest found the two Russian men – Mr Lugovoi and Mr Kovtun – had deliberately poisoned Mr Litvinenko by putting the radioactive substance in his drink at the central London hotel, resulting in an agonizing death.

The European Court of Human Rights (ECHR) also ruled last year, following a case brought by the deceased’s widow, Marina Litvinenko, that Russia was responsible for his murder.

Russia has always denied any involvement in the death and had refused to comply with international arrest warrants issued for Mr. Kovtun and Mr. Lugovoi.

Sir Robert’s Litvinenko inquiry said the use of the radioactive substance – which could only have come from a nuclear reactor – was a “strong indicator” of state involvement.

The investigation also revealed that the two men had probably acted under the direction of the Russian security service, the FSB, for which Mr Litvinenko worked, as well as the KGB.

Possible motives included Mr Litvinenko’s work for British intelligence agencies after fleeing Russia, his criticism of the FSB and his association with other Russian dissidents, while there was also a ‘personal dimension’ to it. antagonism between him and Mr Putin.