Director of Africa programs at Human Rights Watch Daniel Bekele said witnesses to an April raid in the Um Dukhun region of Darfur said former militia leader and police commander Ali Kosheib was seen riding in a government vehicle in the area.
"The evident role of security forces in the Um Dukhun attacks indicates that serious crimes were committed with government knowledge," he said in a statement.
Human Rights Watch reports more than 100 civilians died during fighting among ethnic groups. The group said authorities let state security forces take part in the attacks and few protections were offered to the civilian population.
"The authorities should fully investigate these crimes and hold all those responsible to account," Bekele said from Nairobi.
Kosheib is wanted by the International Criminal Court for war crimes committed in Darfur from 2003 to 2004. Bekele said civilians in Sudan are paying the price for his freedom.