An ABC News investigation revealed visual evidence of a variety of gruesome acts against civilians, allegedly carried by some groups within the Iraqi forces, referred to in the media as the 'dirty brigades'.
The acts include summary executions, torture and beheadings, before posing with the dead bodies or the severed heads – sometimes while smiling. The recorded videos and still images would later be shared with pride on social media platforms, including Instagram and Facebook pages supporting the army and militias.
"Shiite militias have deliberately pushed out very brutal images and a lot of really nasty things," Phillip Smyth, a University of Maryland researcher who specializes in Iraq’s militia activity, was quoted as saying by VoA news on Thursday.
"Fighters are taking this imagery and putting it up ... to kind of demonstrate that they can be tough and just as brutal as the ISIS people and they’re not messing around," he added, while noting that there has been "a real upsurge in terms of quite, quite brutal imagery" since 2014.