Nikolai Glushkov died in London, according to mutliple outlets.
He was given political asylum in 2010 after fleeing the country.
In 2013 Gluskhov said he was one of a few people on a Russian hitlist.
A Russian political exile who once warned that he was on the personal hitlist of Vladimir Putin has died in London in unexplaiend circumstances.
Nikolai Glushkov was found dead at his home in the UK capital, according to multiple UK and Russian media outlets. The exact circumstances are not yet clear.
His death took place in the middle of a diplomatic strom between Moscow and London over the attempted assassination of double agent Sergei Skripal earlier this month.
Glushkov was best-known for being a close associated of Boris Berezovsky, a fellow political exile in Britain who left Russia after falling out with Putin.
Berezovsky was found dead at home in 2013, an incident which had some hallmarks of suicide, but which Gluskhov…