Three Congolese doctors have been arrested in the Democratic Republic of Congo over the killing of a World Health Organization (WHO) medic, a military prosecutor has said.
Cameroonian doctor Richard Mouzoko was shot dead in April at a hospital in Butembo, where he was treating Ebola patients.
The "passionate" medic was "always ready to go where people would need his help most," the WHO said in a tribute.
The motive for the attack is unclear.
More than 1,800 people have died from the Ebola virus in the past year. Efforts to contain the spread have been hindered by militia group violence and by suspicion towards foreign medical assistance.
Senior military prosecutor Lt Col Jean-Baptiste Kumbu told AFP that militiamen involved in attacking treatment centres, including Butembo hospital, had under interrogation implicated four doctors in planning the raids.
He said the three Congolese doctors will be prosecuted for "terrorism" and "criminal conspiracy", according to AFP, while the fourth doctor was still at large.