“We know why Putin killed Alexei three days ago,” Yulia Navalnaya said Monday.

Yulia Navalnaya, wife of late Russian opposition leader Alexei Navalny, accused Russian President Vladimir Putin of being involved her husband’s death and vowed on Monday to continue his work.

“We know why Putin killed Alexei three days ago, we will tell you about it soon,” she said in a video message. “But the main thing we can do for Alexei and for ourselves is to continue to fight. I will continue the work of Alexei Navalny, continue to fight for our country, and I urge you to stand next to me.”

Navalny, a long-time Russian opposition politician and critic of the Kremlin and Russian President Vladimir Putin died in prison at age 47 on Friday, the state prison service said.