A Russian exile and businessman who was friends with a prominent Vladimir Putin critic was found dead from "unexplained" causes in his London home, according to Metropolitan Police.
The department's counterterrorism unit is investigating the death of Nikolai Glushkov due to his associations.
Glushkov was close to oligarch Boris Berezovsky, who was found dead in 2013 under disputed circumstances. He was known for criticizing Putin.
Glushkov's death isn't suspected to be related to the poisoning of former Russian spy Sergei Skripal.
