The United Nations says that ethnic violence in Yumbi, western Democratic Republic of Congo, could constitute crimes against humanity. The medical charity Doctors Without Borders (MSF) has said residents who survived the attacks are still suffering psychologically.
MSF has been working in Yumbi since December, when 535 people were killed the area.
"We are treating people who are exhibiting the same symptoms: weakness, extreme fatigue, lack of energy and motivation, loss of appetite, and insomnia," said Fabrizio Andreolo, MSF project coordinator, who spoke to RFI from Kinshasa. "The population is still greatly suffering, from a psychological point of view."
In its latest report, the UN said that the 535 people killed, along with 111 injured and 16,000 people displaced, were from the Banunu community who were attacked by their Batende neighbours.
"Our investigations indicate that the attacks were well planned and well organised, designed to undermine the physical integrity and property of the Banunu community," said Abdoul Aziz Thioye, Director of the UN Human Rights Office in DRC.
The assailants arrived with war paint, holding firearms, other weapons, and even buckets of fuel used to set homes, churches, and schools on fire.
The attacks, spread over four days, reportedly occurred after a Banunu traditional chief was buried in Yumbi. The Batende people consider Yumbi their territory, and were angered by the provocation.
Many who tried to flee across the river to neighbouring Republic of Congo were killed by the Batende. Investigators said some were burned alive, others thrown into septic tanks. There were a number of cases of victims who were found with genital mutilation.
In the aftermath, MSF carried out an evaluation of what was needed to aid the population's mental health, said Andreolo, who added that those who are having problems come from both communities.
Part of the post-evaluation plan, said Andreolo, was to create discussion groups, which has helped more than 1,000 of the locals. MSF also conducted training for some locally, "with the objective of reassuring the population, calming the population, and orienting them towards other services."
The medical aid association also created dozens of therapeutic groups to help those who are still traumatised by the violence.
"For the most acute cases - around 20 people - we provide individual treatment, as emergency intervention is our mandate at MSF Congo," said Andreolo.
The UN report said Congolese provisional authorities failed to intervene, which facilitated the violence.
"There is no doubt that what has happened in this part of the country is extremely serious.The President of the Republic has launched an investigation mission to Yumbi to conduct independent and impartial investigations to determine the responsibilities," Marie Ange Mushobekwa, Congolese minister of human rights told DRC Radio Okapi, a UN-based radio station.
"On the other hand, it is a mission of the military prosecutor," added the minister.