After the extremist armed group, the Islamic State (also known as ISIS), seized the Iraqi city of Tikrit in June 2014, the blood flowed. ISIS fighters captured and summarily executed hundreds of men, mostly air force cadets who were based at the nearby Speicher military base.

ISIS made no effort to hide its crimes. They posted photos and videos of their fighters leading prisoners to their deaths, and gunmen shooting people in the back. ISIS proudly announced that 1,700 “Shia members of the army” were killed.

Using satellite imagery, Human Rights Watch mapped the crime scene. The aerial and ground imagery revealed five execution sites within the presidential palaces complex in Tikrit where ISIS fighters slaughtered between 560 and 770 men. A survivor gave a detailed account of being captured, feigning death, and managing to escape. At the time, we warned that the death toll was likely to climb.

As Iraqi forces reclaimed territory lost to ISIS, including Tikrit in April 2015, the number indeed began to rise. This week, a group called the Committee to Commemorate the Tikrit Massacre said that 157 bodies had been found in recent weeks, bringing the total number to 1,150.

These atrocities demand justice, but the Iraqi government has so far relied on the heavy hand. It has reportedly detained at least 19,000 people for alleged ISIS ties and Iraqi courts have sentenced more than 3,000 people to death. The trials have been rushed and deeply flawed, including confessions apparently after torture.

Iraqi authorities have forced families with relatives suspected of being ISIS members into prison camps. They have destroyed some of their homes.

Video: Local Authorities Displace Suspected "ISIS-Families" in Iraq

Iraqi forces have forcibly displaced at least 125 families said to have familial ties to affiliates of the Islamic State (also known as ISIS). 

The growing body count in Tikrit is a reminder of the war crimes for which the individuals responsible need to be held to account. The death sentences after show trials and collective punishment of families add another layer of injustice to these terrible crimes.

Fair trials are needed to build trust in the judicial system, to nudge Iraq toward the rule of law, and to break the cycle of killing and revenge.