He said one scout who escaped, as his friends were being killed, had walked for days through the hills, avoiding roads for fear of his life, to tell his gruesome story.
Mr de Besterfeld, a Belgian who has lived in Zaire since 1953 and is commissioner of scouts for the Kivu region, said the scouts, most of them in their late teens, had their hands tied behind their backs before being slaughtered, one by one, with machetes and clubs, five days ago.
The report compounded fears that Rwandan refugee camps are becoming no-go areas for aid workers. The United Nations refugee agency yesterday kept aid workers out of the Katale camp for the fourth day and withdrew its staff from Benaco camp in Tanzania.
Despite a five-hour meeting on Sunday between UN officials, aid workers, Zairean officials and about 150 refugees from Katale camp, there was still no agreement that would allow the aid workers to return to the camp, which is now home to some 270,000 people.
The camps are under the control of former officials of the previous regime in Rwanda, many of whom are responsible for the genocidal massacres that took place earlier this year.
Last Friday, after a dispute over control of food distribution at Katale, one local aid worker was killed and others were threatened. Although the UN High Commissioner for Refugees (UNHCR) continues to refer to the former officials as 'bandits', it has been forced to work with and feed them, even though many wear uniforms and have weapons stored in the camp.
It is against UN rules to treat soldiers as refugees, but one aid worker said: 'You have to work with them if you want to get anything done in the camps . . . they intimidate the refugees and stop them returning to Rwanda, but at the same time the refugees want their protection.'
The trouble has spread to Tanzania, where 500,000 Rwandans are camped.