In August 2014, Islamic State (ISIS) fighters invaded Mount Sinjar, the stronghold of the Yazidis, a Kurdish-speaking religious minority in northern Iraq. Thousands were killed and thousands of women and teenage girls were kidnapped and sexually enslaved.
Nabil Greseque allegedly took part in the attack as an ISIS fighter. His whereabouts are unknown.
In 2016, the prosecutor from the French Specialized Unit for the prosecution of genocide, crimes against humanity, war crimes and torture of the Paris Tribunal (integrated in 2019 within the newly created French National Anti-Terrorist Prosecution Office) opened a preliminary investigation into alleged genocide and crimes humanity perpetrated by ISIS against the Yazidi community in Syria and Iraq.
In 2018 and 2019, the International Federation for Human Rights (FIDH) legally represented Yazidi survivors who gave their testimonies to the investigators, denouncing the participation of French citizens in the crimes they suffered.
On 10 July 2020, a judicial investigation was opened against Greseque for genocide and crimes against humanity committed in Syria against Yazidis between 2015 and 2016.