Police in Lithuania are investigating an attack on the former chief of staff of Alexei Navalny, the late Russian opposition leader. On Tuesday, Leonid Volkov was assaulted with a hammer and had tear gas sprayed in his eyes outside his home in Vilnius, the capital of Lithuania. The attack comes just weeks after Navalny died in a Russian Arctic prison. Leonid Volkov spoke to Reuters just hours before the attack on Tuesday and directly accused Putin of ordering Navalny’s killing.

Leonid Volkov: “But in the moment, this dying dinosaur is very strong and can cause enormous damage. That’s what we’ve seen in the last two years in Ukraine, and that’s what we’ve seen in the situation of the murder of Alexei Navalny. And we have absolutely no doubt. Like, it’s beyond reasonable doubt that it was Putin’ s personal order to kill him on February 16th.”

The attack occurred ahead of this weekend’s election in Russia. Volkov and Navalny’s wife Yulia have called on Russians to join an election day protest at polling places at noon on Sunday.