Russian dissident Alexei Navalny, 47, died in prison this Friday, according to RIA Novosti. The well-known dissident felt unwell after a walk and almost immediately afterward lost consciousness.

He was sentenced to nine years in March 2022 in a “strict regime penal colony” in a fraud case. His lawyers reported that the activist did not receive medicine and only enjoyed an hour and a half walk outside his cell a day. The prison was founded in the 1960s as part of the Soviet forced labor camp gulag system.