The security scenario in Sochi is shaping as having a very errie similarity to the storyline of the 1971 Frederick Forsyth novel The Day of the Jackal.
For those not familiar with that book, it's about a plot to assasinate the President of France. The story revolves around a mysterious sniper who has been retained to commit the crime, with his plan being to target the President during a major outdoor public ceremony in Paris. As the saga unfolds, there are increasingly furious attempts by the French security forces to identify and capture the sniper before the date of the ceremony arrives. But when it does and the sniper remains at large, an impenetrable wall of police and military are placed around the ceremony...
...but the sniper still finds a way to breach it.