A mountain of roses and carnations covers Navalny's grave in Moscow. Lyudmila Navalnaya reaches out and touches her son's portrait.
"I think it will take some time, but we will find out who did it," she told AFP and other media outlets.
For Navalnaya, this weekend's news - that Alexei Navalny was killed by the poison epibatidine, according to a scientific assessment from five European countries - represents a kind of vindication.
It confirms what we knew all along. We knew that our son didn't just die in captivity - he was murdered.
The poison was traced using biological samples smuggled out of Russia. The regime critic's widow, Yulia Navalnaya, blames President Vladimir Putin for her husband's death.
Epibatidine is an extremely potent alkaloid isolated from the skin of poison dart frogs in Ecuador and Peru.
The venom is known for its analgesic effect, but is not used clinically due to its powerful toxicity. Epibatidine is around 100 times more potent than morphine and kills by paralyzing muscles and the respiratory system.
The discovery of the poison was made in the 1970s. Scientists believe that the poison arises through the frogs' diet, since animals from different habitats exhibit different levels of the toxin. Poison dart frogs raised in captivity do not produce any poison at all. However, the toxin can now also be produced in the laboratory.
