The man who helped Vladimir Putin to become a president

"The Fourth Man" compromised the identities of Russian spies working for Washington DC and leaked troves of sensitive CIA data. Ex-CIA agent Robert Baer told The Sun Online the actions of the spy at this time "could have changed history". It is thought that perhaps if "The Fourth Man" had been weeded out - US intelligence would have been able to identify the threat from Putin and warn the Kremlin. He said all conversations between then US President Bill Clinton and then Russian leader Boris Yeltsin were leaked to Putin and the KGB.