Video report by ITV News Security Editor Rohit Kachroo
Sitting next to the leaders of China and Japan, Vladimir Putin insisted Alexander Petrov and Ruslan Boshirov were civilians with "nothing criminal" about their trip to Salisbury.
A fortnight later and it has been claimed that the Russian president himself bestowed the nation's highest military honour on Boshirov, whose real identity is said to be Anatoliy Chepiga, a highly decorated colonel in the GRU intelligence service.
Online investigative group Bellingcat says it has uncovered records that show Col Chepiga was quietly given the Hero of the Russian Federation award around four years ago.
In use since the collapse of the Soviet Union, the honour is issued personally by the president "as recognition of services to the state and the people of Russia involving a heroic deed", the group says.
Medals are usually handed out at public ceremonies and are accompanied by a presidential decree, but they are not announced when the act of heroism is a state secret.
Bellingcat, which is run by British citizen journalist and blogger Elliott Higgins, says it has gathered evidence that Col Chepiga was given the honour in December 2014.
The Home Office said it could neither confirm nor deny the reporting about the suspect’s real identity.
Scotland Yard, which has already said it believed the two suspects were using aliases, declined to comment.
Theresa May attacked Russia's tactics, accusing the country of violating "international norms".
She told world leaders at the UN that Russia's use of "chemical weapons on the streets of Britain by agents of the Russian GRU", which is Russia's military intelligence, had been "reckless".
Earlier this month, the UK accused Petrov and Ruslan Boshirov of the attempted murder of former spy Sergei Skripal and his daughter Yulia in March.
Britain also accused Russia of responding with "obfuscation and lies" after the prime suspects in the Salisbury nerve agent attack claimed they visited the UK as tourists.
Petrov and Boshirov told Russian state-funded news channel RT they travelled to the “wonderful” city in Wiltshire after recommendations from friends.
The pair claimed they have been left fearing for their lives after Britain pointed to their involvement.
Foreign secretary Jeremy Hunt told ITV News that he had warned his Russian equivalent that if they continued to use chemical weapons that the price to pay would be "too high".
"This isn't just a spat between Britain and Russia, we have had a consensus in the world that has been very strong since 1945, that people don't use chemical weapons.
"Hitler used them but apart from that they're really not being used and that's beginning to break down because of what Russia did in Salisbury but also what they allowed to happen in Syria and it would be an absolute tragedy for humanity if we went back.
"These are the most horrible weapons after nuclear weapons, it doesn't get worse than chemical weapons and we've got to maintain the international census amd for that reason my message to Russia is very simple: if you do this the price will be too high."
Russia's President Vladimir Putin said the men had been discounted as members of his security network, and insisted they were civilians.
UK authorities believe the pair smeared the highly toxic chemical Novichok on a door handle at the Wiltshire home of former GRU officer Sergei Skripal, leaving Mr Skripal and his daughter Yulia critically ill on March 4.
On June 30, in nearby Amesbury, Dawn Sturgess, 44, and her partner Charlie Rowley, 45, were exposed to the same nerve agent.
Ms Sturgess died in hospital in July, just over a week after the pair fell ill.
A police officer who visited the home of the Skripals shortly after the attack, Nick Bailey, was also left critically ill from exposure to the substance.