By Robert Walker
The trial of a former Rwandan official accused of being a main perpetrator of the genocide has begun at the UN war crimes tribunal in Tanzania.
Some 800,000 mainly Tutsis were killed in the genocide in 1994
Colonel Tharcisse Renzaho, former prefect of the Rwandan capital, Kigali, faces charges of genocide and complicity in genocide.
Some 800,000 people, most of them Tutsis, were killed by Hutu extremists during the massacres in 1994.
Col Renzaho, who was arrested in DR Congo in 2002, has denied the charges.
During the genocide in Rwanda, Col Renzaho was in control of the capital's police force and local officials.
But rather than using this authority to stop the killings, it is alleged that he incited Hutus to kill members of the Tutsi minority.
The prosecution says Col Renzaho used state radio to instruct the police and army, as well as civilians, to man roadblocks so they could identify and intercept Tutsis.
It is alleged he told local officials that anyone with a Tutsi wife should also be deemed Inyenzi - a cockroach - the term used by Hutu extremists to describe Tutsis.
Col Renzaho faces life imprisonment if convicted.
The international criminal tribunal for Rwanda, based in Arusha in neighbouring Tanzania, is responsible for trying those accused of masterminding the genocide.
But it has often been criticised for operating too slowly.