The wife of late Russian dissident Alexei Navalny said on Thursday that investigators had told her his death in an Arctic prison colony in February was caused by a "combination of diseases" - a finding she rejected as preposterous.
Yulia Navalnaya said she would demand a criminal investigation of her husband's death, which she considers to be murder, and that Navalny's team would continue to conduct its own probe.
Navalny, 47, died suddenly on Feb. 16, depriving the Russian opposition of its most charismatic and popular leader. He had been serving sentences totalling more than 30 years on charges he said were rigged in order to silence his criticism of President Vladimir Putin.
The Kremlin has strongly rejected his supporters' accusation that Putin had him murdered.
Posting on social media, Yulia Navalnaya published a copy of a three-page official letter she received last week stating there were no criminal circumstances surrounding her husband's death and therefore no grounds to open an investigation.