The group, For Human Rights, argues that criminal proceedings should be launched against officials responsible for a police operation that left one protester dead and 12 people wounded.
For Human Rights says a second protester died three days later.
Most of those wounded in the April 25 protest in the town of Usukhchai were police officers.
Police used tear gas and rubber bullets to disperse protesters demanding the resignation of a district administration chief.
RFE/RL Russia Report
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