What is the dart frog toxin allegedly used to kill Alexei Navalny?

The toxin, epibatidine, can be found in frogs in the wild in South America or manufactured in a lab.

Two years later, Navalny’s death still casts a shadow over Russia and wider Europe

Mourners in Moscow have marked two years since Russian opposition leder Alexei Navalny died in an Arctic prison, as a new European analysis fuels claims he was killed by poisoning.

Navalny’s death still casts pall 2 years on

Mourners gathered in Moscow Monday to mark two years since the death in custody of Russian opposition leader Alexei Navalny, under the shadow of a Kremlin crackdown and just two days since a new analysis reinforced suspicions that he was killed by poisoning.
Meduza

Police filmed everyone. Nobody hid. At Alexey Navalny’s grave, on the second anniversary of his death, his mother stood in the freezing cold and listened.

Two days before the second anniversary of Alexey Navalny’s death, five European countries declared that independent forensic analyses show the opposition leader was poisoned in prison. The substance reportedly used to kill Navalny was the neurotoxin epibatidine — an allegation Russian authorities dismissed as “a planted fabrication.
Shropshire Star

Mourners in Moscow mark two-year anniversary of Alexei Navalny’s death

Mourners gathered in Moscow on Monday to mark two years since the death in custody of Russian opposition leader Alexei Navalny, under the shadow of a Kremlin crackdown and just two days since a new analysis reinforced suspicions that he was murdered.