The UK government announced this week that it had concluded its investigation into the attempted assassination of former Russian military intelligence officer turned double agent, Sergei Skripal, in Salisbury, England, earlier this year. Skripal and his daughter were both exposed to a Soviet era nerve agent known as Novichok — a weapon devised specifically by the Soviet Union to circumvent international laws regarding chemical and biological weapons.

Russia has denied any involvement in the attack, going so far as to accuse the UK of conducting it themselves as a sort of “false flag” operation they claim is a part of a grander “anti-Russian conspiracy” that includes UK allies like the United States. Despite Russia’s claims, many in the international community have attributed the attack to an ongoing counter-intelligence effort taking place in Moscow. The specifically Soviet weapon used in the attempt on Skripal and his daughter’s lives is widely considered to have been a message for other potential defectors or double agents: Russia will still come after you, even after decades.

“Security and intelligence agencies have carried out their own investigations,” UK Prime Minister Theresa May said on Wednesday. “I can today tell the House … that the government has concluded that the two individuals named are officers from the Russian intelligence services.”

British authorities also released a number of images of the Russian agents in Salisbury at the time of the attack, including shots from surveillance video taken in both Salisbury and London.

Russia has continued to deny any involvement in the attack, or in the subsequent incident involving the perfume bottle the two men used to disperse the nerve agent. Another local man named Charlie Rowley discovered the discarded Nina Ricci perfume bottle and gave it to his girlfriend, believing it to be nothing more than what it seemed to be: a half full bottle of luxury perfume. She then sprayed it on herself and died as a result of the exposure. Rowley himself fell ill, but survived the ordeal after being hospitalized.

US expels 60 Russian officials in wake of UK nerve agent attack

Read Next: US expels 60 Russian officials in wake of UK nerve agent attack

“The manner in which the bottle was modified leaves no doubt it was a cover for smuggling the weapon into the country, and for the delivery method for the attack against the Skripals’ front door,” May said.

A photo of the fake perfume bottle and applicator containing the nerve agent that poisoned Charlie Rowley and Dawn Sturgess in July. London Metropolitan Police

Russian officials made a series of statements to state-owned media outlets denying Britain’s accusations on Wednesday, including Putin’s aid, Yuri Ushakov, who acted as though he was confused by Theresa May’s statements.

“We heard or saw two names, but these names mean nothing to me personally, just like you, I believe,” he said before claiming that Scotland Yard admitted the named were “contrived.”

“I do not understand why that was done and what signal the British side is sending. That is difficult to comprehend.”