The case is due to be heard on June 8.
The peacekeepers who died during an ambush in the central African nation earlier this month were: Im Sam, Sieng Norin, Mom Tola and Mao Eng.
The Documentation Center of Cambodia has been the most prominent Cambodian institution to research and record the history and suffering under the Khmer Rouge regime from 1975 to 1979.
Since 2014, local rights group Licadho has recorded more than 400 cases of domestic violence, which have led to 40 deaths.
Cambodia has sent more than 3,500 peacekeepers on U.N. missions in Africa and the Middle East over the past 10 years.
VOA Khmer’s Hean Socheata spoke to Sophie Busson of Reporters Without Borders about the situation of press freedom in Southeast Asia and Cambodia.
More than 12,000 people lent their support to the online campaign in solidarity with war refugees.
Venerable Loun Sovath, a central figure in the film, played an active role in documenting protests against land grabbing, as well as teaching human rights and Buddhist practices to land grab victims.
The banners were erected two months ago and taken down on Tuesday during the police raids.
The workers petition for better social security and healthcare provision, a revision of the trade union law, and increased occupational safety protections.
At least 12 journalists have been killed in Cambodia since 1992, while many others have faced legal action over their reporting.
Reports released Friday amount to stunning rebuke of US, which has long seen itself as standard-bearer of free speech and model for countries around world.