Transcript for Video captures the moments just before a Russian spy collapsed from poisoning

Turning overseas now to the quint British city now swarming with hazmat suits. The new surveillance images coming in tonight of his spy and his daughter apparently poisoned. ABC's Jennifer Eccleston with the latest. Reporter: Tonight, new surveillance video capturing the moments just before a Russian spy and his daughter collapsed. Poisoned, on the brink of death. Watch as this man and woman, believed to be sergei skripal and his daughter yulia walk casually in Salisbury, England. British authorities say the poison, a very rare nerve toxin. Tonight, they're still fighting for their lives. As more than 250 counterterrorism police widen the crime scene across this normally quiet city. We want explanations. Reporter: Hazmat teams blocking off the graves of skripal's son. Hunting for possible contamination. So far, more than 200 witnesses questioned. This is a serious, substantial investigation. Reporter: Sergei skripal was a former Russian spy, turned double agent for the British, convicted in Russia and released to the uk in a spy swap. British government officials calling the attempted assassination outrageous. Tom, investigators not naming suspects yet. But some lawmakers here already blaming Moscow, noting that Russia has a history of using poisons against alleged traitors. Tom. Jennifer, thank you. Still ahead on "World news

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