The nerve agent that poisoned two people in Wiltshire was contained inside a perfume bottle, according to the brother of one of the victims.
Dawn Sturgess was killed, and her partner Charlie Rowley was left severely ill, after they were both exposed to Novichok in Amesbury more than two weeks ago.
Matthew Rowley said his brother Charlie told him that he had picked up the perfume bottle.
The Metropolitan Police - who only said that the nerve agent was found in a “small bottle” inside the victim's home - refused to confirm the claim.
Matthew Rowley told BBC News he was still upset about his brother's condition after speaking to him on the telephone.
Charlie is "absolutely not the brother I know" following the poisoning, Mr Rowley said.
Investigators believe the incident is linked to the novichok poisoning of former Russian spy Sergei Skripal and his daughter Yulia in Salisbury in March.
Police are investigating the possibility the culprit discarded a novichok container that was picked up unwittingly by Ms Sturgess and Mr Rowley four months later.
Earlier this week, people in the Amesbury and Salisbury areas were told not to pick up "containers, syringes, needles, cosmetics or similar objects" by the chief medical officer at Public Health England.