Well the knowns were not so unknown after all:
Days after the bombing of a Shiite shrine unleashed a wave of retaliatory killings of Sunnis, the leading Shiite party in Iraq's governing coalition directed the Health Ministry to stop tabulating execution-style shootings, according to a ministry official familiar with the recording of deaths.
The official, who spoke on the condition that he not be named because he feared for his safety, said a representative of the Shiite party, the Supreme Council for the Islamic Revolution in Iraq, ordered that government hospitals and morgues catalogue deaths caused by bombings or clashes with insurgents, but not by execution-style shootings...
...Abductions and killings of Sunni Arab men, usually by gunshots to the back of the head, have occurred with increasing frequency over the past year and are widely blamed on government-allied Shiite religious militias and death squads alleged to be operating from inside the SCIRI-dominated Interior Ministry. In particular, Shiite militias have been accused of abducting and executing large numbers of Sunni men in the days immediately following the Feb. 22 destruction of the Askariya mosque, a revered Shiite shrine in the northern city of Samarra.
Well, surely we can admit that a bullet in the back of the head is much more free-ish than what Saddam used to do?!