Troops serving under Mike Mikombe opened fire in the eastern city of Goma on members of a religious sect taking part in a banned protest against the UN peacekeeping force. 

He was charged with crimes against humanity.

Three fellow officers have also been convicted by a military tribunal and sentenced to 10 years in prison. 

Col Mikombe's lawyers have said they'll appeal.

The death sentence is often handed down in DR Congo but it's been more than 20 years since an execution took place.