LONDON (AFP, NYTIMES) - A police officer tested for possible exposure to the nerve agent Novichok in connection with the poisoning of a couple in southwest England on Saturday (July 7) was given the all clear, the local force said.
"Pleased to confirm that the police officer who sought precautionary medical advice at Salisbury District Hospital in connection with the incident in Amesbury has been assessed & given the all-clear," Wiltshire Police said on Twitter.
Meanwhile, the couple remained in critical condition, breathing with the assistance of ventilators and surrounded by the world's leading experts on Novichok poisoning, their odds of survival being closely tracked by Britain and Russia.
Ms Dawn Sturgess, 44, and Mr Charlie Rowley, 45, were exposed a week ago to traces of a Soviet-developed nerve agent. They likely came into contact with it by picking up a vial, syringe or ampule discarded by a would-be assassin who took to the city of Salisbury in southern England months ago to target a former Russian spy Sergei Skripal, police said.
Mr Skripal and his daughter, Yulia, were poisoned by the same type of nerve agent in March. A British police officer also became sick after responding to the poisoning of the Skripals. They have since recovered.
The British government accused Russia of trying to kill the Skripals, a charge that Moscow angrily denied, sparking an international crisis.
In the latest case, if either of the couple dies, "it becomes a murder investigation, and it's involving a British national rather than a Russian national", said Mr James Nixey, head of the Russia and Eurasia programme at Chatham House, a research group in London.
That would present British and Russian authorities with a new diplomatic scenario.
British ministers have said that a link between the two cases is a main line of inquiry, and the government has asked Moscow to help provide answers about what has happened.
Several sites in both Amesbury and Salisbury have been cordoned off by emergency services.
Salisbury hospital said it had seen "a number of members of the public who have come to the hospital with health concerns since this incident started and none have required any treatment".
"We would like to reiterate the advice from Public Health England that the risk to the wider public remains low," it said.
Novichok is a military-grade nerve agent developed by the Soviet Union during the Cold War.
Around 100 counter-terrorism officers are helping in the investigation into the latest poisoning, which police said last Friday could "take weeks and months to complete".
So far, there is no evidence that the British couple visited any of the sites involved in the Skripal case.
The British couple had been in treatment after years of substance abuse, which compromises the liver's function as the body's detoxifier. That makes them more physically fragile than the victims in Salisbury.