Officials are conducting a thorough search at Queen Elizabeth Gardens in Salisbury "for a number of days".
A coroner on Thursday opened an inquest into the death of a British woman who was exposed to a military grade nerve agent, while British media reported that police may have identified suspects in an attack that poisoned a former Russian spy with the same deadly substance.
"The cause of death will not be given until further tests are completed", coroner David Ridley said. It was adjourned until January.
45 year old Charlie Rowley, from Muggleton Road in Amesbury, fell ill on 30th June hours after his partner Dawn Sturgess, 44, collapsed after being exposed to novichok.
Meanwhile, Mr Hope has said it could be "weeks or even months" before his mother can be buried - and claimed police told him that her body is now "property of the Crown".
"Work is ongoing to establish whether the nerve agent is from the same batch as used in the attack against Sergei and Yulia Skripal in March, and this remains a main line of enquiry for the investigation team", the police said in a statement.
Sturgess died July 8, while Rowley has regained consciousness and is in stable condition.
The government has blamed the attack on Moscow. Police believe they came into contact with the substance via the door handle of Sergei Skripal's house.
Several Russians were involved in the attempted murders, a source with knowledge of the investigation told PA, adding that their identities were confirmed by cross-checking security footage with records of people entering the country around that time. The Press Association reported that police have examined closed-circuit TV footage and cross-checked it with records of people who entered the United Kingdom around the time the Skripals fell ill.
Earlier this month, Dawn Sturgess and Charlie Rowley were hospitalized after falling ill, and investigators determined they had been exposed to the Russian-made poison Novichok.
A police spokesman declined to comment on the report.
British officials reportedly believe that Russian Federation is "desperate" to know what is happening in the Scotland Yard inquiry and have attempted to hack into it.
Russian Federation has strongly denied poisoning the Skripals, sparking a diplomatic row that has led to tit-for-tat diplomatic expulsions between Britain and its allies and Russian Federation.
Ridley, the coroner, said samples taken from both Sturgess and Rowley tested positive for Novichok at Britain's defense research labs. They do not apportion blame.