MOSCOW -- Russian investigators say they have traced back the steps of a poisoned Russian spy's daughter from her Moscow home to the airport before she flew to London, and found no traces of poison. Sergei Skripal and his daughter Yulia were poisoned in Britain with a military-grade nerve agent last month.

Yulia Skripal lives in Moscow and was visiting her father, which led British investigators to believe that she might have unwittingly carried the substance with her.

Britain blames Russia for the attack, which it says was carried out by smearing the Soviet-developed nerve agent on a door handle at Skripal's house in Salisbury. Moscow denies involvement.

Russia's Investigative Committee late Wednesday released online CCTV footage from Moscow's Sheremetyevo airport and said it had traced Skripal's taxi cab ride and her movements around the airport. The investigators said they identified everyone on Skripal's flight and said none of the passengers displayed any symptoms of poisoning.

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The footage released by the committee on its official YouTube account shows a woman who looks like Skripal get out of the taxi outside the terminal, go through security and board the plane.

The investigators also expressed their frustration at Britain's unwillingness to share information about the probe.