British police have launched a murder investigation into the death of Russian political exile Nikolai Glushkov, who was found dead in his London home earlier this week, The Guardian reports. Glushkov was a friend of Russian oligarch Boris Berezovsky, a noted critic of Russian President Vladimir Putin, who was found dead in the U.K. in 2013. Police said the cause of Glushkov's death was "compression to the neck," Reuters reports.
Glushkov's death follows the poisoning of a former Russian spy and his daughter with a nerve agent earlier this month. The U.S. and U.K. governments have blamed Russia for the attack. Police said that there is no known link between Glushkov's death and the attempted murder of the father and daughter at this point.
Scotland Yard's counter-terrorism unit continues to lead the investigation into Glushkov's death, citing "associations Mr. Glushkov is believed to have had."
Glushkov was arrested in Russia in 2000 for embezzling funds from the national airline Aeroflot, where he served as deputy director, CNN reports. He was sentenced to three years in prison in Moscow in 2004, and received political asylum in the U.K. in 2010. He was later questioned over the death of former Russian spy Alexander Litvinenko, who was killed after drinking tea laced with radioactive polonium in London in 2006.