London, Great Britain—The British Government has identified two Russian nationals as the main suspects for the poisoning of a former Russian spy and his daughter.

The Scotland Yard and the Crown Prosecution Service (CPS) has named Alexander Petrov and Ruslan Boshirov as the main perpetrators. They are believed to be working for the Russian military intelligence service, GRU, under aliases.

Last March, Sergei Skripal and his daughter Yulia Skripal were poisoned with the nerve agent Novichok. A British law enforcement officer, Detective Sergeant Nick Bailey, was also contaminated whilst responding to the attack. The GRU agents sprayed Skripal’s house door in Salisbury with a perfume bottle containing the Novichok agent.

Two British citizens were also poisoned by Novichok. Dawn Sturgess and Charlie Rowley found the perfume bottle in question in a charity box. Trying to open it, they became contaminated. Unfortunately, Sturgess died in the hospital; Rowley was discharged earlier this summer.

“It now forms one investigation. We do not believe Dawn and Charlie were deliberately targeted but became victims as a result of the recklessness in which such a toxic nerve agent was disposed of,” said Neil Basu, the head of UK counter-terrorism policing.

British Prime Minister Theresa May identified the men as members of the GRU and accused the Russian Government of direct involvement, stressing that this wasn’t a standalone operation.

“We must now step up our collective efforts specifically against the GRU. [We will use] the full range of tools from across our national security apparatus” she added.

The Russian ambassador in London responded by accusing Mrs May of “politicized public accusation” and of uncooperativeness. “The fact that you have two photos and two maybe fake names doesn’t mean too much,” added Andrey Kortunov, director general of the Russian International Affairs Council.