The nerve agent that poisoned two people in Amesbury was contained in a perfume bottle, the brother of one of the victims has claimed.
Matthew Rowley said his brother Charlie, who remains seriously ill in Salisbury hospital, told him that he had picked up the perfume bottle, the Daily Telegraph reports.
The claim will raise the question of whether Dawn Sturgess, who died just over a week after being poisoned by the deadly nerve agent, sprayed the perfume on herself, effectively self-administering a lethal dose of Novichok.
Detectives are urgently working to establish how the perfume bottle came to be in the flat, and whether the Novichok it contains comes from the same batch used in the attack on former Russian agent Sergei Skripal and his daughter, Yulia on March 4.
One theory is that Rowley, 45, and Sturgess, 44, had been contaminated when they picked up the container after finding it hidden under a bush in a park in the centre of Salisbury on June 30.
While the main source of the contamination has now been located, police have warned there could be more traces of Novichok at other locations around Wiltshire.
Several key sites, including Rowley's Amesbury address and Sturgess' flat in Salisbury remain in sealed off and police have warned that the cordons would remain in place for some considerable time.
Rowley's brother Matthew, who has spoken to him on the phone, told BBC News he was "absolutely not the brother I know".
Rowley's condition continues to improve in hospital and he is now eating solid food, but Sturgess - a mother of three - died just over a week after being poisoned by the deadly nerve agent.
Her son, Ewan Hope, has called for US President, Donald Trump, to raise the Novichok poisoning with the Russian leader, Vladimir Putin when he holds talks with him in Helsinki tonight NZT.
The Russian state has denied any involvement in the attempted hit on Skripal, but the Government has said there is no other plausible explanation for how the Soviet era nerve agent came to be used on the streets of Britain.
Hope said: "I don't share Trump's politics and I'll never be a supporter of his, but I would like him to raise mum's case with the Russian President.
"We need to get justice for my mum. I am so angry with her killers."
Sturgess' family have been told it could be months before her body can be released for the funeral to take place.