It was one of the most daring acts of the Cold War that could have come directly from the pages of a spy novel.
In 1978, Georgi Markov was caught with an umbrella that shot a poison grain in his leg while crossing Waterloo Bridge in London while waiting for a bus.
He died three days later – and for nearly 40 years, mystery has surrounded the whereabouts of his murderer.
Georgi Markov stung an umbrella that shot a poison grain in his leg
A replica of the umbrella that a KGB agent used in 1978 to kill the Bulgarian dissident
Former KGB agent Alexander Litvinenko was poisoned in London in 2006, a murder that a judge said was probably approved by President Vladimir Putin.
The defector died after two agents slid radioactive polonium 210 into his teapot at a Mayfair hotel in central London.
The 43-year-old had been an officer with the Federal Security Service (FSB), but he fled to Britain, where he became a fierce critic of the Kremlin.
He died after a tormenting six-day battle in the hospital.
Former KGB agent Alexander Litvinenko was poisoned in London in 2006 when a radioactive substance was poured into his teapot in a Mayfair hotel
Alexander Perepilichnyy, a key witness in a £ 140 million tax fraud investigation, collapsed while jogging outside his £ 3 million mansion in Weybridge, Surrey, in November 2012.
The Russian had taken gelsemium – a very rare poisonous plant that only occurs in China, a coroner heard.
Tests conducted by leading botanist Professor Monique Simmonds from Kew Gardens found a chemical in Mr Perepilichnyy's stomach that could only come from a variety of gelsemium – a well-known method of murder by Chinese and Russian contract killers.
Alexander Perepilichnyy collapsed during jogging outside his £ 3 million mansion in Weybridge, Surrey, in November 2012
A radiation expert who is responsible for the & # 39; murder & # 39; of Alexander Litvinenko, was found dead five months after a trip to Russia in a mysterious suicide.
Matthew Puncher, 46, bled to death in his home from multiple stab wounds caused by two knives in his home in Drayton, Oxfordshire in May 2016.
A pathologist said that he could not exclude the possibility that someone else was involved in death, but concluded that the injuries were self-inflicting.
Radiation expert Matthew Puncher, who reported the & # 39; murder & # 39; by Alexander Litvinenko, was found dead in May 2016 in a mysterious suicide
Boris Berezovsky, was found dead in his bathroom in Berkshire with a ligature around his neck in March 2013.
His friends in the secret service say he intended to give Putin evidence of a plot involving oligarchs to overthrow the strong man in a coup.
Theory wants the exiled Russian tycoon to be killed by Western secret services related to the plan to overthrow the leader of the Kremlin.
A coroner registered an open verdict in which he said he either took his own life or was killed and the scene was staged to appear inflicted on himself.
Boris Berezovsky, found dead in his bathroom in Berkshire with a ligature around his neck in March 2013, but the coroner has pronounced an open verdict
Bankrupt property tycoon Scot Young was the fifth member of a close circle of friends who died in unusual circumstances.
The 52-year-old was fatally wounded after falling out of a window on the railing after being hunted by debts of Russian Mafia members.
They had previously dangled him out of a window at the Dorchester Hotel in Park Lane and threatened to drop him next time if he didn't pay, his good friend claimed.
Young, once worth an estimated £ 400 million, claimed to have lost his fortune when a huge Russian real estate deal called Project Project collapsed in 2006.
Bankrupt property of tycoon Scot Young (photo on the right) was fatally injured after he fell out of a window on the railing after being chased by debts of Russian Mafia members
Meanwhile, the German Gorbuntsov survived in 2012, despite being shot several times with a submachine gun on the Isle of Dogs in East London.
The Russian banker reportedly had evidence relevant to the attempted murder of the Russian billionaire Alexander Antonov.
In 2016, former Russian double agent Colonel Alexander Poteyev, who exposed glamor spy Anna Chapman, died in the US.
Poteyev had supervised the Russian sleepers in the US as deputy head of the & # 39; S & # 39; department of the Russian foreign intelligence service.
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