Teams of specialist officers are continuing their forensic search for traces of novichok at Queen Elizabeth Gardens in Salisbury.
Wearing protective suits to avoid being contaminated by hazardous materials, the officers have also put on gas masks.
They started their search of public toilets yesterday and resumed the investigation earlier today.
The toilets are cordoned off with protective screens, and swabs have also been taken from a park bench.
Sky News’ Lisa Dowd, who is at the scene, said: “This is believed to be one of the areas where Charlie Rowley and Dawn Sturgess visited before they fell ill.
“The forensic intensification at this scene will probably continue throughout the day.”
Mr Rowley and Ms Sturgess were exposed to the deadly nerve agent after handling a contaminated bottle later found at Mr Rowley’s home in Amesbury, near Salisbury.
In March, the Wiltshire cathedral city was the scene of the novichok poisoning of former Russian spy Sergei Skripal and his daughter Yulia, who both survived.
Admitted to hospital on 30 June, Ms Sturgess, 44, later died, while Mr Rowley, 45, was discharged on Friday, three weeks after falling ill.
Mr Rowley’s brother, Matthew, told Sky News he was “ecstatic” at his brother’s release from hospital, but expressed surprise at his swift recovery given only a few days previously he had still seemed very weak.
Mr Rowley said: “He’s obviously improved in his condition.
“He was very weak. He could barely lift his head off the pillow. He had lots of tubes… and a lot of machines around him.
“Obviously he’s stronger than I thought.”
Mr Rowley said his brother’s recollection of what happened was “very vague”, but added: “He definitely said to me that they found this bottle of something and Dawn sprayed it on her wrists and that he picked it up and broke it somehow – and that’s how he got it on his hands.”
Public Health England medical director Paul Cosford has said Mr Rowley’s discharge from hospital does not pose a risk to the public.
He added: “Our advice to the public remains unchanged. Do not pick up any items such as syringes, needles, cosmetics or similar objects made of materials such as metal, plastic or glass.
“If you didn’t drop it, then don’t pick it up.”
Detectives are investigating the possibility – described by Mr Rowley’s brother – that Ms Sturgess tested the spray on her face and hands, believing it to be perfume.
The mother-of-three’s death is being treated as murder.
The results of a post-mortem could help establish whether the novichok was from the same batch used to poison the Skripals.
Police are believed to have identified the suspects behind the March attack.
From – SkyNews