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 says it has gathered evidence that Col Chepiga was given the honour in December 2014.
A state-run volunteer website says he was given the award for conducting a “peace-keeping mission”, while the award was also mentioned online by his military school, according to the group.
The school does not explain why he was given the medal, saying only that it was “by decree from the Russian president”.
Col Chepiga’s name also features alongside other recipients on a memorial wall at the military school, the group says.
Bellingcat has said that the “phrasing and timing” of the award suggests it may be linked to Russia’s clandestine activity in Eastern Ukraine.
In 2014 there were no military activities in Chechnya and Russia had not engaged in Syria.
The group’s disclosures came after Theresa May revealed British spies had gathered evidence that indicated the suspected assassins behind the attempted murder of Sergei Skripal were GRU officers.
“This was not a rogue operation. It was almost certainly also approved outside the GRU at a senior level of the Russian state,” she told the Commons.
Mr Putin later addressed the allegations during a question and answer session with Japanese Prime Minister Shinzo Abe of Japan and Chinese President Xi Jinping at the Easter Economic Forum in Vladivostok.
“Of course, we looked who these people are. We know who they are, we have found them already,” the Russian president said.
“There is nothing special and nothing criminal about it, I”m telling you...they are civilians.”
On Wednesday, a spokeswoman for the Russian Foreign Ministry dismissed Bellingcat’s claims, and said they were part of an “information campaign” to distract from the investigation into what really happened in Salisbury.