Among those who knew Sergei Skripal in the quiet English city of Salisbury, few seem to have been aware of his background as a spy and British-Russian double agent. He frequented local pubs, bought lottery scratch cards in corner shops and joined a social club alongside local men in their 60s.

On Sunday, that past seems to have caught up with him. Skripal and daughter Yulia were poisoned by what British authorities say was a sophisticated nerve agent. They are now hospitalized in critical condition. A policeman who responded to their collapse on a bench outside a shopping center was also exposed and his condition is classed as "serious."

The Times newspaper reported Thursday that Britain's MI5 believed Moscow was behind the poisoning. Russia's Foreign Ministry has denied the charges.