The death of a 68-year-old Russian man in London is being investigated by counter-terrorism police, Scotland Yard has said.
While officers are not naming him, he is believed to be businessman Nikolai Glushkov, who was top of a list of "fugitives from justice" published by the Russian embassy which accused him of committing "severe financial offences".
Scotland Yard said anti-terror police were investigating his death "as a precaution because of associations that the man is believed to have had".
But there was "no evidence", it said, "to suggest a link to the incident in Salisbury", adding that the death was being treated as "unexplained".
One of Mr Glushkov's friends was the late Russian oligarch Boris Berezovsky who fled to London in 2000 following a row with Vladimir Putin.
Mr Glushkov, a former deputy director of the Russian airline Aeroflot, had also worked for Mr Berezovsky's LogoVAZ car company.
After Mr Berezovsky was found hanged in the bathroom of his Berkshire home in March 2013, Mr Glushkov told The Guardian he would "never believe" his friend took his own life.
An inquest into Mr Berezovsky's death recorded an open verdict.
Mr Berezovsky was also a friend of Russian dissident Alexander Litvinenko, who was poisoned with radioactive polonium-210 in London in 2006.
Sure, but you can manufacture C4 outside of a lab too. That attack you quoted had a fatality rate of 8/500 people, that's... What, 2%? This isn't some homebrew. Not to defend rinks though, waste of time.
nerve agents are only as good as the dispersal method - the Japan attacks limited effectiveness ( ) were down to a misunderstanding of the properties of what theyd created/how to properly use it - not the nerve agent itself.
- The UK will now expel 23 Russian diplomats who have been identified as undeclared intelligence officers. "All who been identified as undeclared intelligence officers. They have just one week to leave," she says. "This will be the single biggest expulsion for over 30 years and it will reflect the fact that this is not the first time the Russian state has acted against our country."
- There will now be increased checks on private flights, customs and freezing of Russian state assets. The UK prime minister says she hopes there will be cross party support for these measures. "There is no place for these people or their money in our country," she says.
- There will be no attendance of ministers or the Royal Family to this year's World Cup.
- The organisation of the Prohibition of Chemical Weapons had been notified.
- Theresa May says she welcomes strong expressions of support from Nato and partners from across the EU against Russia.
- New legislative powers are to be developed to harden defences against all forms of hostile state activity against the UK, Theresa May says.
BBC News wrote:Labour leader Jeremy Corbyn in response says the UK must be guided by the rule of law, support for international agreements and respect for human rights against Russia.
"Our response must be decisive and proportionate and based on clear evidence," he says.
Labour leader Jeremy Corbyn asks the PM how she has responded to Russian calls for a sample of the nerve agent. There are cries of "disgraceful" from the Conservative benches.
He also calls for Mrs May to update the House on conversations she has had with the Russian government.
Jeremy Corbyn says it's "a matter of huge regret" that the country's diplomatic capacity has been stripped back over the past five years.
"The measures we take have to be effective not just for the long term security of citizens but to make the world free of chemical weapons," he adds.
BBC News wrote:"The measures we take have to be effective not just for the long term security of citizens but to make the world free of chemical weapons," he adds.
Obviously most people wish for a world that doesn’t have these sort of weapons in it.
But those weapons exist. They will continue to exist. Nobody is going to give them up.
So it is a nice thought to dream of a world with no chemical weapons, but Corbyn is having a strawberry floating laugh if he thinks Russia are going to give them up based on any response that the UK can give.