The Islamic State (IS) group is responsible for heinous war crimes which in some cases also constitute crimes against humanity.

When the guns fall silent after an IS massacre there is no frantic rush on the part of those responsible to hide the evidence of their war crimes and, in many cases, crimes against humanity. In fact so happy is that group to claim credit for mass-murder that it often exaggerates the death toll.

Cast your mind back to just last June of this year. IS had rapidly overrun Mosul. The Iraqi Army was in disarray and unable to put up a fight. IS rapidly made gains seizing, among other places, Tikrit. In mid-June IS proudly proclaimed it had executed a whopping 1,700 “Shi’a members of the [Iraqi] army” there.

Human Rights Watch has investigated the incident and established that there were indeed executions of “at least 160” in that area. Those it executed had been lined up alongside trenches already dug and shot so their bodies would land in the trenches. Eerily similar to how Nazi Germany’s specialist Einsatzgruppen death squads used to execute Soviet Jews en-masse during the German invasion of the Soviet Union in World War II.

Human Rights Watch have also recently gathered evidence of more war crimes in Iraq carried out by IS last June. In a report, “Iraq: ISIS Executed Hundreds of Prison Inmates” the human rights group describes in detail how IS systemically executed 600 inmates of a prison near Mosul.

As was the case with Tikrit it appears they targeted the Shia and even went to the trouble of separating the Shia Muslims from the Sunni Muslims – remember IS deplore adherents of the Shia branch of Islam more than they do most other religions due to the fact they see the Shia as heretical Muslims. As was the case in Tikrit those people were forced to lean by a ravine before they were shot dead. Smaller numbers of Kurds and Yezidi’s were amongst those IS killed from that prison.

More recently in Anbar IS have purportedly killed at least 300-members of the Sunni Albu Nimr tribe who revolted against their rule over their homeland. That group had previously fought against the al-Qaeda in Iraq group from which IS split more recently and like many Sunnis in Iraq do not see IS as a representative of their beliefs and ambitions.

The Albu Nimr members were massacred in a fashion characteristic of IS’s methods. They seized the territory and kill anyone in their way. And they seem to take considerable pleasure in doing the latter as it exemplified from the gory execution videos they promote with great eagerness and enthusiasm.

One recent incident saw to them once again line up those men and women and execute them in the village of Ras al-Maa north of the Iraqi city of Ramadi, Anbar’s capital. It is clear they were killed for resisting IS’s brutal domination of that province.

It is unlikely that these atrocities will stop any time soon. If anything the worst has yet to come. The predominantly Shiite government in Baghdad is reforming and trying to get its act together and mount a counter-offensive to re-seize Mosul and the northern parts of Iraq IS overran last June and also dig them out of the Anbar province.

But to do so requires greater integration. One of the predominant grievances the Albu Nimr tribesmen had was the fact they weren’t allowed into the Iraq Security Forces after the 2007 surge where they gave a valuable service to all of Iraq when they helped to quash and seriously dislodge the al-Qaeda in Iraq group there. Since that time the quasi-sectarian government of former Prime Minister Nouri al-Maliki marginalized them like it did to many of Iraq’s Sunnis.

The need for a Sunni Awakening in order to afflict a decisive defeat on IS is of vital importance. That much is obvious. But without substantial reform in the ranks of the central government and an outreach to the Sunnis of Iraq that consists primarily of clear and concrete action, as opposed to warm words and rhetoric, aimed at enabling and empowering Iraq’s Sunnis and showing them they have a chance to shake off their IS rulers.

Because without such an empowerment IS will likely continue its atrocities largely unabated.