Human Rights Watch has urged Iraqi authorities to give a government committee charged with probing a deadly raid by security forces on a protest camp last week greater financial and political backing to investigate who is responsible for what it described as an apparently unlawful use of lethal force.
On Saturday, the group also said it received photos from a separate, parliamentary investigation allegedly taken in the aftermath of the attack that showed the bodies of several men lying in the protest area amid burning cars.
Some have their hands bound and "appear, because of the way the bodies are positioned, to have been executed with gunshots,'' the group said.
The April 23 action against the Sunnis in Hawija who were protesting against the Shia-led government unleashed a backlash of deadly attacks by Sunnis, and battles between gunmen and security forces that have claimed more than 250 lives.
Before the Hawija crackdown, local and tribal officials had been trying to negotiate a peaceful end to a standoff between protesters and security forces.
Authorities had wanted to enter the camp to hunt for weapons and make arrests related to an earlier incident in which a nearby checkpoint came under attack.
Iraqi forces opened fire only after they were attacked, according to the Defense Ministry.
It said 23 people, including three members of the security forces, were killed in the clashes.
It said "only insurgents and extremists remained" in the camp before it moved in, and that some of the dead included fighters with ties to al-Qaeda and Saddam Hussein's outlawed Baath Party.
The Defense Ministry has said security forces opened fire only after they came under attack while trying to make arrests.
Hours after the raid, Prime Minister Nouri al-Maliki ordered the creation of a ministerial committee to investigate the incident.
A parliamentary committee is also probing what happened at Hawija.
Human Rights Watch obtained a preliminary copy of the parliamentary investigation's findings.
It said the committee determined that the crackdown by security forces on the Hawija camp killed at least 44 civilians.
All were killed by live fire, and at least one of the dead was 13 years old, Human Rights Watch said.
The committee's casualty figures are similar to ones provided by Deputy Prime Minister Saleh al-Mutlaq, who leads the separate ministerial committee that is also investigating the Hawija incident.
His office said 46 people not on the side of security forces, including minors, were killed.
Al-Mutlaq's committee has based its findings primarily on interviews with government officials and on photographs from the scene.
He acknowledged difficulties in speaking to witnesses among the protesters because they are afraid to participate in the process.
The parliamentary committee inquiry, meanwhile, is based in part on interviews with witnesses who were at the protest.
It did not talk to soldiers who were at the scene because it claims it was prevented from doing so by their superior officers, according to Human Rights Watch.
The parliamentary committee report "indicates that senior officials gave orders for army, federal police, and SWAT forces, all of which fall under Maliki's military office, to invade the demonstration site, remove demonstrators and level tents," the rights group said.
While it alleges that senior officials, including al-Maliki, may have ordered the raid, "it does not address what orders they issued concerning the use of force," according to the group.
Al-Maliki's spokesman, Ali al-Moussawi, denied that any orders were given to fire on protesters.
"There is no need to ask who issued the orders, because those orders did not exist in the first place," he said.