FILE - In this Wednesday, Aug. 9, 2006 file photo, Sergei Skripal speaks to his lawyer from behind bars seen on a screen of a monitor outside a courtroom in Moscow. It has been reported on Monday, March 5, 2018 by the British media that Skripal is in critical condition after exposure to 'unknown substance' in English city of Salisbury. (AP Photo/Misha Japaridze, File)
Who is Sergei Skripal?
Former Russian spy Sergei Skripal has been left critically ill after being exposed to an 'unknown substance'. CNN's Nick Paton Walsh takes a look at the man behind the headlines.
01:56 - Source: CNN
Russia in World Affairs 16 videos
FILE - In this Wednesday, Aug. 9, 2006 file photo, Sergei Skripal speaks to his lawyer from behind bars seen on a screen of a monitor outside a courtroom in Moscow. It has been reported on Monday, March 5, 2018 by the British media that Skripal is in critical condition after exposure to 'unknown substance' in English city of Salisbury. (AP Photo/Misha Japaridze, File)
Who is Sergei Skripal?
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(L/R): Head of Dutch Military Intelligence and Security Service Onno Eichelsheim, Minister of Defence Ank Bijleveld and British ambassador Peter Wilson attend a press conference of the Dutch Military Intelligence and Security Service (MIVD) at The Hague, The Netherlands, on October 4, 2018. - Dutch intelligence thwarted a Russian cyber attack targeting the global chemical weapons watchdog in April and expelled four Russian agents, the government said. The Russians set up a car full of electronic equipment in the car park of a hotel next to the Organisation for the Prohibition for Chemical Weapons in The Hague in a bid to hack its computer system, it said. (Photo by Bart Maat / ANP / AFP) / Netherlands OUT        (Photo credit should read BART MAAT/AFP/Getty Images)
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The UK will expel 23 Russian diplomats from the country after concluding that the Russian state is responsible for the attempted murder of former Russian agent, Sergei Skripal and his daughter Yulia in Salisbury on March 4th.  They will have one week to leave.   "For those who seek to do us harm, my message is simple. You are not welcome here."
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A Russian flag flies next to the US embassy building in Moscow on July 31, 2017. (MLADEN ANTONOV/AFP/Getty Images)
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 Steven Seagal (R) delivers a press conference with Costa Rican President, Oscar Arias (out of frame), on February 11, 2009, at the presidential residence in San Jose. Seagal and Arias met to talk about the possibility of real estate and film industry investments in Costa Rica. AFP PHOTO/ Mayela LOPEZ (Photo credit should read MAYELA LOPEZ/AFP/Getty Images)
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SALISBURY, ENGLAND - JULY 05:  A police officer stands by a cordon in place at Queen Elizabeth Gardens in Salisbury after a major incident was declared when a man and woman were exposed to the Novichok nerve agent on July 5, 2018 in Salisbury, England. The couple, named locally as Dawn Sturgess 44, and Charlie Rowley, 45 were taken to Salisbury District Hospital on Saturday and remain there in a critical condition. In March Russian former spy Sergei Skripal and his 33-year-old daughter Yulia were poisoned with the Russian-made Novichok in the town of Salisbury. British Prime Minister Theresa May has accused Russia of being behind the attack on the former spy and his daughter, expelling 23 Russian diplomats in retaliation. (Photo by Jack Taylor/Getty Images)
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Yulia Skripal poses for the media during an interview in n London, Wednesday May 23, 2018. Yulia Skripal says recovery has been slow and painful, in first interview since nerve agent poisoning. (Dylan Martinez/Pool via AP)
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A Russian flag flies next to the US embassy building in Moscow on March 27, 2018. (MLADEN ANTONOV/AFP/Getty Images)
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Presidential candidate, President Vladimir Putin addresses the crowd during a rally and a concert celebrating the fourth anniversary of Russia's annexation of Crimea at Manezhnaya Square in Moscow on March 18, 2018. / AFP PHOTO / POOL / Alexander Zemlianichenko        (Photo credit should read ALEXANDER ZEMLIANICHENKO/AFP/Getty Images)
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Russian President Vladimir Putin delivers a speech during a meeting with Russian athletes and team members, who will take part in the upcoming 2018 Pyeongchang Winter Olympic Games, at the Novo-Ogaryovo state residence outside Moscow on January 31, 2018. / AFP PHOTO / SPUTNIK / Alexey NIKOLSKYALEXEY NIKOLSKY/AFP/Getty Images
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