The attack on the Skripals has plunged relations between Russian Federation and Britain to a new low, and sparked a wider diplomatic crisis that saw Russian Federation and Britain's Western allies expelling hundreds of diplomats.
"Investigators believe they have identified the suspected perpetrators of the Novichok attack", an unidentified source told the Associated Press.
The UK's Press Association report said police had analysed closed-circuit television and believed several Russians were involved in the attack on the Skripals.
Reuters contributed reporting to this article.
The Metropolitan Police, who are leading the investigation, declined to comment.
One of the Amesbury victims, Dawn Sturgess, died on July 8.
Sergei Skripal and his daughter Yulia were poisoned in March 2018.
"It is not an exaggeration to say that the search process linked with both this and the Salisbury investigation has been one of the most complex and hard that United Kingdom policing has ever faced", Assistant Police Commissioner Neil Basu said on Friday.
Victims Dawn Sturgess left and Julia Skripal
The substance, which was in liquid form, is believed to have been discarded in a perfume bottle that was later found by Sturgess and Rowley in a park or somewhere in Salisbury city centre.
From the very beginning, British authorities have pointed the finger at Russia for the Skripal poisoning, but have yet to present any evidence of Russian involvement.
Last week counter-terrorism detectives revealed they had found a small bottle containing Novichok at Mr Rowley's home in Muggleton Road, Amesbury. Sturgess apparently sprayed the agent onto her skin.
She, along with her partner Charlie Rowley, who remains in a serious condition, was poisoned in Amesbury, a Wiltshire town just eight miles from Salisbury - where the Skripals were attacked.
Inquests are medical and legal hearings conducted in Britain in cases of unnatural, sudden or violent death.
In April, the Organisation for the Prohibition of Chemical Weapons (OPCW) confirmed the UK's finding that Novichok was used in the attack. They set out to determine the place and time of death as well as how the deceased came by their death, but do not apportion blame.
The team completed its work Wednesday and will submit the samples for analysis, according to the OPCW.
"These are media reports, unfortunately there are no official statements from the British side".