An investigative journalism website has published what it says is the real identity of one of the Russian intelligence officers suspected of the Salisbury nerve agent poisoning.
The Bellingcat group claims the man who was named as Ruslan Boshirov is actually Colonel Anatoliy Chepiga.
British officials have not commented. The BBC understands there is no dispute over the identification.
UK investigators have said Mr Boshirov was a Russian intelligence officer.
It was thought he travelled to the UK on a false passport, under a pseudonym, with another Russian national who used the name Alexander Petrov.
Ex-spy Sergei Skripal and his daughter Yulia were poisoned by Novichok in March. The pair survived but Dawn Sturgess - a woman not connected to the original attack - died in July after being exposed to the same substance.
The UK government has accused Mr Petrov and Mr Boshirov of the attack. It said they were undercover officers for the Russian military intelligence, the GRU.
Russia has always denied the allegations and President Vladimir Putin said the suspects were civilians.
The pair then appeared on Russian-state television claiming to have been tourists, visiting Salisbury to see its cathedral.
Bellingcat says that Col Chepiga was a soldier who served in Chechnya and was awarded the highest state award - Hero of the Russian Federation, usually bestowed personally by President Vladimir Putin.
Bellingcat obtained extracts from the passport file of Anatoliy Vladimirovich Chepiga. A picture of Mr Chepiga from 2003 appears to look like a younger version of the man who used the identity Ruslan Bushirov.