Transcript for Nerve toxin that sickened Russian colonel, daughter 'very rare': Authorities

Now to the fast-moving investigation tonight. 180 soldiers moving into the community in the uk trained in chemical warfare after that former Russian spy and his daughter were poisoned. Our chief foreign correspondent, Terry Moran is on the scene tonight. Reporter: As technicians in hazmat gear fanned out across key Salisbury today bagging evidence, the military also moved in. 180 troops, trained in chemical warfare. Some removing possibly contaminated police vehicles. Hazmat crews even erected a tent over the graves of sergei skripal's wife and son. Skripal may have visited here before the attack. The weapon, a nerve toxin, described by authorities as a very rare agent that could only have been produced by a few laboratories in the world. Skripal, a former colonel in the Russian army who was caught spying for Britain in 2006 and was later released in a spy swap, by all accounts led a quiet life in this quiet city. Skripal and his daughter left the Italian restaurant at the end of that passageway, cros over this bridge, and collapsed onto the park bench there, now covered by a tent, already fighting for their lives. For the people of Salisbury, the widening probe is worrying. So you still feel like there is a threat? Yep, absolutely. Until it's all been resolved, a lot of people are going to sit there and worry about it without any explanation.' Reporter: Experts say the rare toxin used here suggests government involvement in this chemical weapons attack, and they note that Russia has a history of using poiso again alleged traitors. David? Terry Moran with us again tonight, and we're learning more

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