UN state they have evidence that ISIS has killed 670 Shia inmates from Mosul prison. According to the guardian ISIS fighters sorted inmates based on their faith, asked Sunnis to recite prayer and identify their backgrounds. Then took Shia to some desert like area, placed them in four rows, and shot them as they kneeled. Some survived by playing dead and reported the story to UN.
This massacre that took place in June 2014 was strongly condemned by Navi Pillay, the UN high commissioner for human rights.
Earlier ISIS forced women to engage in sexual relationship with fighters as they destroyed Shia properties and killed its residences.
