three man says security force members shot , killed prisoners as Amnesty International fighters approached . A woman says she found brother 's body among many others at Amnesty International facility . Amnesty International alleges that government forces , Sunni militias executed Shiite detainees . Human Rights Watch finds mass graves thought to hold those killed by ISIS fighters , their allies .
One man says security force members shot , killed prisoners as ISIS fighters approached . A woman says she found brother 's body among many others at Tal Afar facility . Amnesty International alleges that government forces , Shiite militias executed Sunni detainees . Human Rights Watch finds mass graves thought to hold those killed by ISIS fighters , their allies .