But there was "no evidence", it said, "to suggest a link to the incident in Salisbury", adding that the death is being treated as "unexplained".
Police did not release the man's name saying the man had not been formally identified.
Late Russian oligarch Boris Berezovsky, who died in London in 2013, was associated with Russian exile businessman Nikolai Glushkov, who was found dead late Monday in his London home.
His death took place in the middle of a diplomatic storm between Moscow and London over the attempted assassination of double agent Sergei Skripal earlier this month.
Scotland Yard said anti-terror police were investigating Mr Glushkov's death "as a precaution because of associations that the man is believed to have had".
In 2000, he was arrested in connection with the embezzlement of Aeroflot's funds, and later charged with fraud and money laundering. His family has been informed and a post-mortem examination will be held in due course. "The death is now being treated as unexplained", he said. "If there is a change in the status of the investigation, an update will be provided", the Met said.
Glushkov received political asylum in Britain after serving five years in prison in Russian Federation for money laundering and fraud, the Guardian newspaper reported.
Glushkov, who has been an executive at state airline Aeroflot and also worked for Berezovsky's auto company LogoVAZ, followed and was granted asylum in 2010.
Berezovsky, a powerful oligarch and one-time supporter of Putin who turned against his former protege, was found hanged in a bathroom at his home outside London in 2013.
Berezovsky is one of 14 Russians whom U.S. intelligence services believe were assassinated in the United Kingdom, according to an investigation by BuzzFeed News.
In March last year, he was sentenced to eight years in prison in absentia and issued a one million Russian Ruble fine for allegedly defrauding Aeroflot of $122 million during his tenure as finance director there in the late 1990s.
