The group, Bellingcat, said Wednesday that the suspect, whose passport name was Ruslan Boshirov, is in fact Col. Anatoliy Chepiga, who in 2014 was awarded Russia's highest medal, the Hero of Russian Federation.
He is one of two men now in Russian Federation who are wanted by the British authorities for the attempted murder of Sergei Skripal and his daughter Yulia, in March.
The Foreign Office did not comment but the BBC said it understood officials did not dispute the revelations by investigative website Bellingcat.
Bellingcat said it had received tips from former Russian military officers and perused pictures of graduates of Russian military academies.
Prime Minister Theresa May did not address the reports directly in a speech to the United Nations in NY, but spoke of "the reckless use of chemical weapons on the streets of Britain by agents of the Russian GRU (military intelligence)".
Investigative website Bellingcat has concluded that Chepiga is in fact an undercover officer of GRU, along with his suspected accomplice "Alexander Petrov" - which is also an alias.
It has now emerged that he fought for a feared special forces Spetsnaz unit - which is under the command of the GRU - for 17 years, and worked for at least nine.
It "would imply that 'the job was ordered at the highest level, '" the group quoted its source as saying, according to Agence France-Presse.
Former Russian military intelligence colonel Sergei Skripal attends a hearing at the Moscow District Military Court in Moscow on August 9, 2006.
Russian President Vladimir Putin said this month he knew who the two suspects were, and that they were "civilians, of course".
The website bills itself as "the home of online investigations" and its report on the man it revealed to be Colonel Anatoliy Chepiga has made headlines around the world.
It is not clear why he received the award. The journalists said they also acquired parts of Chepiga's passport file including a photograph of him dated to 2003 that closely resembled "Boshirev".
A passport photo of the man now identified as Colonel Anatoliy Chepiga from 2009 (Bellingcat/PA)What has Russian Federation said?
ONE of the men accused of poisoning Sergei Skripal in the English country town of Salisbury has been outed as a highly awarded intelligence officer in Russian Federation.
The pair survived the attack but two more people were poisoned and one of the victims, Dawn Sturgess, died in July.