The United Nations tribunal handling remaining Rwanda genocide cases said it will investigate the circumstances surrounding the death of Félicien Kabuga, the genocide suspect who died in custody in The Hague at the age of over 90, according to an Associated Press report.

Kabuga, accused of financing and encouraging the 1994 Rwanda genocide, died Thursday in a hospital in The Hague while under detention by the International Residual Mechanism for Criminal Tribunals (IRMCT), the U.N. body responsible for remaining Rwanda and former Yugoslavia war crimes cases.

In a statement, the tribunal said it would “conduct an inquiry into the circumstances surrounding the death of Kabuga while in custody,” after his case had remained unresolved since 2023 when judges ruled he was medically unfit to stand trial due to dementia.

Kabuga had been one of the last major fugitives linked to the genocide that killed around 800,000 people, mostly Tutsis, during a 100-day massacre in Rwanda in 1994. Prosecutors accused him of funding and supporting the Interahamwe militia and backing the extremist RTLM radio station, which allegedly incited violence and identified Tutsi targets during the killings.

The United Nations’ historical overview describes the genocide as one of the deadliest episodes of mass violence in modern African history.

After decades on the run, Kabuga was arrested near Paris in 2020 following an international manhunt. His trial later stalled after judges determined he could no longer meaningfully participate in proceedings because of declining health.

The IRMCT case file had previously detailed charges including genocide, incitement to commit genocide and crimes against humanity.

Kabuga’s lawyer, Emmanuel Altit, criticized the continued detention of his client despite the court’s ruling that he was unfit for trial, arguing that his imprisonment no longer served a judicial purpose.