Glance: Other Russians whose deaths have rocked UK

Russia's transition from a Kremlin-controlled economy to a free market free-for-all in the 1990s brought on a wave of contract killings as criminals, entrepreneurs and corrupt officials tried to muscle each other out of lucrative businesses. The death of 67-year-old Boris Berezovsky - who died from hanging at his home, according to initial post mortem examinations - has raised questions about the safety of oligarchs as opposition figures back in Russia have been making the United Kingdom their home.

Here are some other U.K. incidents involving figures from - or involved with - the former Soviet Union:

ALEXANDER LITVINENKO

Litvinenko, a former KGB agent turned fierce critic of the Kremlin, died after ingesting polonium in his tea at a London hotel in 2006. His family blames the Russian state for orchestrating his death, and British authorities have named former KGB officer and Russian lawmaker Andrei Lugovoi as their chief suspect. The Kremlin - and Lugovoi - deny being behind the poisoning, which drew headlines worldwide. Perhaps mindful of Litvinenko's experience, British police called in a hazardous materials team to examine Berezovsky's home. They later declared the property clear of hazardous materials.

BADRI PATARKATSISHVILI

Patarkatsishvili, an associate and confidant of Berezovsky's, died in his mansion in southern England in February 2008. Police initially said his death appeared suspicious but authorities later ruled the 52-year-old billionaire had succumbed to heart failure. Patarkatsishvili was active in Georgian politics, retained a small army of bodyguards, and often said he feared he would be targeted in an assassination attempt.

ALEXANDER PEREPILICHNYY

Perepilichnyy was found dead outside his plush home in southern England in November 2012. He had been in possession of documents which allegedly blew the lid off a massive Russian tax fraud involving dirty money being funneled into Swiss bank accounts. Post-mortem examinations have so far failed to determine how the 44-year-old died. In a recent report, the BBC said he had had a checkup and was given a clean bill of health only months before his death.

STEPHEN CURTIS

Described by author Mark Hollingsworth as "the lawyer who knew too much," Curtis died when his helicopter crashed in poor weather on its way to his 19th-century retreat in southern England in March 2004. Investigators ruled the crash was an accident, but Curtis was a big player in the murky world of Russian banking and had recently been receiving death threats.

GERMAN GORBUNTSOV

Russian businessman Gorbuntsov was shot six times in London's Canary Wharf financial district in March 2011. Gorbuntsov - who survived - blames disgruntled business associates for the attack. So far no one has been brought to justice.