Human Rights Watch says:
Gunning down prisoners is an outrageous violation of international law. While the world rightly denounces the atrocious acts of ISIS, it should not turn a blind eye to sectarian killing sprees by government and pro-government forces.
HRW documented five massacres of prisoners in June.
Human Rights Watch documented five massacres of prisoners between June 9 and 21 – in Mosul and Tal Afar in northern Nineveh province, in Baaquba and Jumarkhe in eastern Diyala province, and in Rawa in western Anbar province.
In most cases the prisoners were shot, but:
In one case the killers also set dozens of prisoners on fire, and in two cases they threw grenades into cells.
In a sixth massacre in Hilla (Babil), which was investigated by Reuters:
police executed 69 prisoners in their cells in the city of Hilla before transferring their bodies to Baghdad later that day.
This is the massacre I wrote about here, questioning the police claim that ISIS attacked the prisoner convoy. As it turned out, the prisoners were killed in their cells and their bodies were being transported. Reuters reported:
The police account there also was that the prisoners had died in the crossfire during a battle with insurgents. But local Sunni officials including the mayor and the provincial governor, medical staff at the morgue and relatives of the dead all said the victims were gunned down in their jail cells.
...Several police sources interviewed by Reuters said prisoners were being preemptively killed in Iraq to prevent militant groups from freeing them to rejoin the rebellion.
This is outrageous:
The second Hilla police officer said summary executions were routinely carried out by army and police forces.
“First thing we do is to shoot them in foot and then take their confessions. Then we kill them and write in report they were killed in action,” he said, also on condition of anonymity.
Another official told Reuters:
A senior local official in Hilla said the attack on the convoy had been staged to hide the execution.
"The police brought the bodies of 16 other terrorists they had executed earlier to the scene and laid weapons by their corpses to pretend they had attacked the convoy," he said.
The Wall St Journal is sticking with its version that ISIS attacked the convoy causing the death of 81 people. If the prisoners were killed by police forces in their cells and the convoy was transferring dead bodies, how did ISIS cause their deaths?