New York - UN experts say they are not ruling out the possible involvement of Democratic Republic of Congo state security forces in the murder of two of their colleagues.
In a confidential report seen by AFP on Tuesday, the group of experts says it has conducted preliminary analysis of phone records, a video and interviews on the March 12 murder of American Michael Sharp and Swedish-Chilean Zaida Catalan.
"The preliminary evidence does not yet allow the group to attribute responsibility for the murder," reads the report by the experts to the Security Council.
"However, the available evidence does not preclude the involvement of different actors, such as pro- or anti-government Kamwina Nsapu factions, other armed groups as well as members of state security services."
The bodies of Sharp, the group's coordinator and arms expert, and Catalan, a humanitarian expert, were found in a shallow grave by peacekeepers weeks after they disappeared. Catalan had been decapitated.
The report sent to the council in late June says the two experts were "executed by a heteroclite group of individuals not yet identified at the time of writing."
But it goes on to describe the murder as a "premeditated setup" after the pair set out on a field investigation from Kananga on March 12.
On the eve of the field trip, the pair spoke to members of the clan leader's family, according to an audio tape of the meeting obtained by the group.
Sharp and Catalan had been tracking the "alarming levels" of violence since August 2016 when Congolese troops killed Jean-Pierre Mpandi, the customary chief of the Kamwina Nsapu clan, says the report.
In response, the militia launched attacks targeting state agents and symbols, prompting the army to launch offensives against the insurgents "often using disproportionate violence," it adds.
Throughout 2017, the insurrection grew into a "larger upheaval" involving many factions hostile to Kinshasa but also "pro-government militias," according to the report.
More than 80 mass graves have been identified in the Kasai, the UN said last week.
Two men were put on trial for the murders of Sharp and Catalan and there have been arrests, but the group of experts said "other key suspects" have not been detained despite available evidence.
The experts said they spoke to a senior police officer who "denounced the lack of cooperation of the government security services involved in the investigation."
The murders of Sharp and Catalan were an "attack on the United Nations Security Council," the group said, urging the top UN body to establish an international independent investigation to identify the murderers.
The experts receive their mandate from the Security Council whose resolutions call for regular reporting on possible violations by the panels.
Sweden and the United States have sent investigators to the DRC to find those responsible for the murders, while the United Nations has established a board of inquiry expected to present its findings this month.