Police said that given the deadly dose, the British couple were believed to have become exposed to Novichok by handling a "contaminated item" - with speculation that it could have been the container used to administer the nerve agent to the Skripals.
Sturgess died at Salisbury District Hospital, the same facility that nursed the critically ill Skripals.
"Dawn will always be remembered by us as a gentle soul who was generous to a fault", they said in a statement released through local police.
The brother of 45-year-old Charlie Rowley also said he had visited him and he was talking, but looked "like a skeleton" and could barely lift his head.
Russian Federation has denied any involvement in the Skripal case and suggested the British security services carried out the attack to stoke anti-Moscow hysteria, an assertion London calls absurd.More news: Marvel's Black Widow finally lands a director
A Wiltshire Police spokesman said: "We have arranged the transportation of a auto from an address in Swindon this evening in relation to the on-going incident in Amesbury".
"Charlie Rowley has made further progress overnight".
Britain's public health authority acknowledged on Friday the concerns of people living in the area after the two incidents involving Novichok, but said it was confident that the risk to the public remained low.
They spent weeks in Salisbury District Hospital, where they underwent treatment for suspected exposure to the Russian-created nerve agent Novichok.More news: Nets Trade Jeremy Lin to the Hawks
Rowley, who fell ill on June 30 at his home in Amesbury near Salisbury, had regained consciousness.
AC Basu said 100 detectives were working on the investigation, which was now focused on Ms Sturgess's address within John Baker House in Salisbury, Mr Rowley's address in Muggleton Road, Amesbury, and an area in the Queen Elizabeth Gardens in Salisbury. She died on Sunday.
Public Health England said the risk to the public is low, but warned against picking up "any odd items such as needles, syringes or unusual containers".
"I simply cannot offer a guarantee" regarding public safety, said the head of anti-terrorism Neil Basu during a press briefing in London, before calling on the population not to pick up objects such as syringes or unusual containers ".
Originally from Durrington (South West England), she had three children, an 11-year-old girl and two boys aged 19 and 23, said the police chief.More news: Time machine throne speech transports province to the '90s: Opposition
Assistant Commissioner Basu told residents: "This is murder, you know it's murder, so I don't need to stiffen the resolve of the detectives who are working on this case to try and get justice for Dawn, her family and everyone who has been affected, including this community".