Transcript for Another nerve agent poisoning exposed to a couple in UK town

Overseas to that mysterious poisoning inengland. It couple now confirmed to H beenickened by the same NER age that nea killed aormer Russian spy and hisdaughter. A tiny amount C be de. Tonight, the ent area on edge, as inigators, you see themthere,ook for where T couple might been poisoned. ABC's Eva pilgrs on the scene tonight. Reporter: Tonight, growing mystery. Countertersm investigators trying to zero in on how two itish nationals were poisoned with the deadly E ent novichok. New surveillance footage sho on them app healthy less than 24rs before she and another were rushed to a ital. This is the second unprecedented incident. Itl raise a huge lev of public concern and aty. Reporter: This quiet commy now holding its breath. We've been aluad. Rally I had a knock on my door saying,ve got to pack your bag." Reporter: Officials retracing the stepsf dawn Sturgess and crlie ro, identified by friends in British media. Locations in Amesbury andeven S away in Salisbury, England, shut down. This park cordoned off N where former Russian spy sergei skripal and his daughter yulia were seen just before th collapsed from the Sam type of poison in March. He police, I know, will be no stone unturned. Reporter: Police say they have yet to officially tie th two cases together. We have sort of the murder weapon. We have the location. But what wn'have is any of the suspects and how all those parts came tog Repr: Tonight, the British co in critical condition, beingated at the by the same doctors who successfully saved the skripals' life.now, authorities say the Risko the public is low, but they are tell pple whoisited their Ed off areas T wash their clothes. Tom? Eva pilgrim for U tonight, thank And there ill much more

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