NATO, US, Canada, Australia & 25 European countries expel a total of 152 Russian envoys over Russian former spy poisoning

[contestgamer]

Hiku said:

contestgamer said:

Obviously you can't explain what you know nothing about. They're made guilty either way

Like I just said to the person I responded to above, U.K. intelligence agencies concluded that it was "highly likely" that Russia was behind it.
Absent of concrete definitive evidence (in many cases where the culprits are outside of your jurisdiction, there will never be any such evidence to find), that may very well be the highest level of certainty in their grading system, as it sounds very similar to the highest grading the CIA, FBI and NSA use. Which was with "high confidence."

Only Russia can know for 100% certain whether they did it or not and they've clearly stated they didn't.