A crop circle in the shape of a chemical weapon symbol has appeared in a field near to where two people were exposed to the nerve agent Novichok.
The 53m (175ft) wide formation was spotted in a field on Coneybury Hill near Stonehenge in Wiltshire on Sunday.
It is thought to be a tribute to Dawn Sturgess who fell ill in Amesbury and died on Sunday. Charlie Rowley remains in a critical but stable condition.
Crop circle investigator Steven Grant, said it was proving "controversial".
Since the beginning of the year, around 15 crop circle formations have cropped up across the county.
Mr Grant said the large formation, which appeared overnight in the wheat field near Salisbury, was "unusual".
"We do get crop circles that seem relevant to what's going on," he said.
"But this one is quite controversial, people think it's a bit distasteful but I don't think it is meant to be disrespectful."
Microlight pilot and crop circle enthusiast Matthew Williams said he was "100 per cent positive" the chemical weapon symbol was intended as a "warning about the use of such weapons".
"The circle was actually created the day before the untimely passing of Dawn Sturgess," he said.
"It would never be intended in any other way than to warn of the use of such weapons and to highlight the plight of the victims."
Ms Sturgess lived in Salisbury and she had been in the city with her partner Mr Rowley before going to his flat in nearby Amesbury on 29 June.
They both then fell ill the next day and Ms Sturgess died eight days later.
Their symptoms were the same as those of Sergei and Yulia Skripal.
Mr Skripal, a Russian former spy, and his daughter were poisoned with Novichok in March, in Salisbury.