United Nations investigators tracking one of the most notorious killers in the Rwandan genocide believe he is hiding in Zimbabwe and are launching a new effort to convince authorities in Harare to allow the 60-year-old fugitive to face trial. Protais Mpiranya, the former commander of the presidential guard of the Rwandan army, has been on the run for 27 years charged with war crimes, genocide and crimes against humanity. The ex-soldier is top of a list of remaining fugitives indicted by an international tribunal into the 1994 killings, which left 800,000 people dead in Rwanda, mostly from the Tutsi ethnic minority but also some Hutus. Mpiranya had been second on the wanted list before the arrest of Felicien Kabuga, a former businessman alleged to have helped finance the genocide, on the outskirts of Paris in May. The US war crimes reward programme has offered a $5m reward for information leading to Mpiranya’s arrest. Serge Brammertz, the prosecutor of the body charged with tracking down the fugitive alleged criminals, which is known as the International Residual Mechanism for Criminal Tribunals (IRMCT), said he was hoping to capitalise on the detention of Kabuga to corner Mpiranya. Kabuga now faces charges of playing a key role in the genocide, and if convicted he is likely to spend the rest of his life in prison. “We hope that the arrest of Kabuga would generate momentum and we are hoping to use this to get Mpiranya,” Brammertz said. Investigators have long suspected Mpiranya of hiding in Zimbabwe and have made repeated attempts to convince local authorities to hand over the suspect. Officials from the IRMCT travelled to Zimbabwe months after President Robert Mugabe was forced from power in November 2017 in the hope that the new government would prove more helpful than the former regime. There has been no progress, however, and a new request for assistance is to be made this month. Brammertz said hopes had been boosted by an agreement on legal cooperation on criminal matters signed last month by Zimbabwe and Rwanda. “Because of his military background it is very possible that [Mpiranya] still enjoys protection from senior military officers,” Brammertz told the Guardian. “We think he … is still quite active, still doing business and until recently has been moving around in east and central Africa, possibly between Zimbabwe, the DRC and South Africa.” Relations between governments of the Democratic Republic of the Congo and Rwanda have improved recently, and this could limit options for the fugitive if Zimbabwe becomes unsafe. DRC may now offer a less secure haven for the fugitive, investigators said. “As commander of the presidential guard we consider [Mpiranya] as being one of the main perpetrators of the genocide,” Brammertz said. The genocide began after Rwanda’s Hutu president Juvenal Habyarimana was killed when his plane was shot down over Kigali on 6 April 1994. On Wednesday France marked the 27th anniversary of the start of the slaughter by declassifying and making accessible to the public all documents mentio