BERLIN (AP) — A German court says the former head of a Rwandan rebel group has died in prison while awaiting retrial on war crimes charges.

Ignace Murwanashyaka, the former president of the Democratic Forces for the Liberation of Rwanda, was convicted by a Stuttgart court in 2015 of leading a terrorist organization and four counts of being an accessory to war crimes in eastern Congo in 2009.

The conviction was overturned last year and a retrial was pending.

The court said Wednesday that Murwanashyaka’s health deteriorated suddenly on April 11. He died in a hospital.

The FDLR is made up mostly of Hutu refugees from Rwanda who took shelter in neighboring Congo after the 1994 genocide in which over 800,000 people were killed, most of them ethnic Tutsis but also moderate Hutus.