Will we ever know what really happened to Putin critic Alexei Navalny?

Moscow has been blamed for a series of high-profile attacks that have often involved poison. But, Oliver Carroll writes, we're unlikely to ever uncover the truth

In one of the last photos taken before his alleged poisoning, Alexei Navalny (centre) poses for a selfie alongside his press secretary Kira Yarmysh (foreground left), on their way to board an aircraft at Tomsk airport in Siberia (AP)

In the muddled mystery of Aleksei Navalny’s sudden, unexplained sickness, there are no hard facts.

Authorities have offered limited, and often contradictory information. Their latest explanation for the Kremlin critic’s unconscious state borders on the absurd: metabolic imbalances caused by low blood sugar.

What they aren’t doing is behaving like they have any interest in proving their innocence.