Russian killings in the UK are nothing new, and there were plenty of evidences in many previous cases. What's new here, is that the UK decided to make this particular case public. Unlike, for instance, in 2012[1]:
> Perepilichnyy, who faced repeated threats after fleeing to Britain, was found dead outside his home in Surrey after returning from a mysterious trip to Paris in 2012. Despite an expert detecting signs of a fatal plant poison in his stomach, the British police have insisted there was no evidence of foul play, and Theresa May’s government has invoked national security powers to withhold evidence from the inquest into his cause of death – which is ongoing.
> The prime minister directed the government’s successful bid to withhold documents from Perepilichnyy’s inquest on national security grounds, and as home secretary her department oversaw the police force that concluded the whistleblower’s death was not suspicious.
[1] https://www.buzzfeed.com/heidiblake/poison-in-the-system
In 2014 Scot Young died after falling/jumping from window.
He said he'd been dangled out of windows by Russian heavies previously.
Key bits are not entirely from open sources, particularly the passport application that directly connects the apparently real identity they dug up to the new undercover one.
How can it be considered open source? None of the reports (from several publications) involving the passport applications have identified the source.
There's a name collision where "open source" means something different in intelligence and reporting than it does for software and technology.
A couple of Russians saying that they found the wintry weather in the UK challenging? Well...
"that quality enshrined in a man who, having killed his mother and father, throws himself on the mercy of the court because he is an orphan"
https://ru.wikipedia.org/wiki/%D0%AD%D0%BF%D0%B0%D1%82%D0%B0...
Yet, with so many obvious giveaways, I find it hard to believe Russia ever wanted to get away with the Skripal poisoning. From using a very exotic Russian-made poison to the absurd Salisbury Cathedral story, it looks like a provocation or trolling. Of course, the Russian government will officially deny any involvement, but they are doing it with an obvious wink.