British police are dealing with the second major investigation involving the nerve agent this year, after the poisoning of Sergei and Yulia Skripal in March.
"The spines were weakening", Nixey said of the British authorities, "and if there are new crimes or misdemeanors on the part of the Russian state, then it means that those spines can be restiffened".
While the United Kingdom and the United States blamed Russian Federation for the attack on the Skripals, authorities have not assigned blame for the latest incident, and it's unclear if the cases are related.
At this point in the investigation, Sturgess and Rowley appear to have been two regular British citizens with no apparent connection to Russian Federation, the report said.
The poisoning of the Skripals, who were found slumped over on a park bench in Salisbury, sparked a minor global incident, with the United Kingdom blaming Russian Federation and Moscow denying all responsibility.
Hobson said that Sturgess was living in a homeless hostel in Salisbury and Rowley was a drug user who lived in Amesbury, a small town about eight miles (13 kilometres) north of Salisbury. "We simply don't know".
Mr Javid told the House of Commons: "The use of chemical weapons anywhere is barbaric and inhumane".
Just a few milligrams of the odorless liquid - the weight of a snowflake - were enough to kill a person within minutes.
A witness told Sky News that one of the victims had appeared to be foaming at the mouth, "sweating loads, dribbling and. making amusing noises".
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Police have been unable to locate the source of the contamination and have not ruled out the possibility of more people falling ill from coming into contact with the substance left over after the Skripals were targeted.
"It's shocking, and it's scary", said Elaine Read, a worker at The Kings Arms pub who used to occasionally share a pint with Dawn Sturgess, one of the victims.
Police said there was no evidence the latest victims had visited any of the sites linked to the Skripals, which have since been decontaminated.
The Skripals spent weeks in critical condition after being attacked in the southwest England city of Salisbury in March.
Andrea Sella, professor of inorganic chemistry at University College London, said Novichok nerve agents "are created to be quite persistent - they hang around in the environment, neither evaporating nor decomposing quickly".
A police officer has been taken to hospital for specialist tests over concerns of possible exposure to the nerve agent Novichok. The safety of the public and our officers remains paramount and the searches will take longer because of the precautions that we must take to ensure there is no outstanding risk.
As noted by Deborah Haynes, the defence editor for the Times, the most likely explanation for the subsequent poisoning is that they came into contact with remaining residue from the Skripal attack.
Wallace did add, however, that he is "waiting for the phone call from the Russian state - the offer is there".