Another mass grave was found by Iraqi paramilitary forces near Mosul on Saturday, AFP reported.
The mass grave, containing remains of hundreds of people, was discovered at the Badoush prison after it was recaptured from the Islamic State (IS).
According to Iraqi military, the grave contained around 500 people which marries up with Human Rights Watch (HRW) report of IS killings at Badoush. According to the HRW report, IS executed up to 600 inmates from Badoush prison by rounding them up at the edge of a nearby ravine on 10 June, 2014.
Also 500 Yazidi women were held by IS at the Badoush prison, according to Iraqi lawmaker Vian Dakhil.
A survey from last year of mass graves in Syria and Iraq then identified 72 sites in which Islamic State buried victims of its atrocities. Associated Press assessed that up to 15,000 victims of genocide and mass slaughter may be buried across the territory where IS have been present.
However, IS are not the only ones guilty of massacres and mass graves in the country. Many mass graves have been discovered since the US-led invasion of Iraq toppled Saddam Hussein, mostly containing remains of Shia Muslims and ethnic Kurds killed for opposing the regime between 1983 and 1991.
The operation to retake Mosul from IS was launched in October last year. So far, the Iraqi has retaken the eastern parts of the city and is currently attempting to push IS out from the Western Mosul.