Two military officers have been relieved of their commands as a result of the litany of mistakes, but neither faced criminal charges, a military official familiar with the investigation told The Associated Press on Wednesday.
A report on the investigation said the platoon leader and company commander — whose names were not released — failed to provide proper supervision to the unit or enforce military standards.
A seven-page summary of the investigation provided to the AP also said it appeared insurgents may have rehearsed the attack two days earlier, and that Iraqi security forces near the soldiers' outpost probably saw and heard the attack and "chose to not become an active participant in the attack on either side."
"This was an event caused by numerous acts of complacency, and a lack of standards at the platoon level," said the investigating officer, Lt. Col. Timothy Daugherty, in the summary.
Three 101st Airborne Division soldiers were killed in the June 16, 2006, attack. Spc. David J. Babineau, of Springfield, Massachusetts, was found dead at the scene, and two others — Pfc. Kristian Menchaca of Houston and Pfc. Thomas Tucker of Madras, Oregon — were abducted. Their mutilated bodies were found three days later, tied together and booby-trapped with bombs.
Details of the attack and what led up to it came as thousands of U.S. and Iraqi forces were scouring the same area near Youssifiyah, in what is called the Triangle of Death, for three soldiers believed to have been abducted Saturday by an al Qaeda-related group.
According to the investigation of last June's attack, Tucker, Menchaca and Babineau were ordered to guard a mobile bridge over a canal in order to prevent insurgents from planting mines. Other members of their platoon, who were at two locations up to three-quarters of a mile away, heard small arms fire at 7:49 p.m. When they arrived at the checkpoint about 25 minutes later, Babineau was dead and the others were gone.
Daugherty said the soldiers had been told to stand guard for up to 36 hours with just one Humvee, and there were no barriers on the road to slow access to them or provide early warning.
To expect them to operate an observation post for 24 to 36 hours was unrealistic, he said. "From the time a vehicle was seen, it would have been in front or beside the (Humvee) in a matter of seconds," he wrote.
Daugherty concluded that the platoon did not get the supervision or direction it needed. And he said the unit was hurt by the loss of 10 troops, including several leaders, who were killed in action as well as by the need to shuffle the platoon's leadership three times.
The platoon also had been dogged by an ongoing investigation into the rape and killing of an Iraqi girl and the killing of her family by several other members of the unit.
Daugherty said there was no malicious intent by the officers who were leading the unit.
"Although the leaders in this platoon care and are staying in the fight, the platoon is frayed," he said in his report.
Daugherty's investigation found no evidence linking the three soldiers' deaths to the rape-murder, which occurred three months earlier. An al Qaeda-linked group, the Mujahedeen Shura Council, claimed in July that the attack on Babineau, Menchaca and Tucker was revenge for the rape-killing.
In other developments:
Thurman, who is now commander of Fifth Corps in Heidelberg, Germany, also accepted Daugherty's recommendations that the platoon be ordered to stand down for 10 days to address combat stress and get refresher training. In addition, administrative actions were taken against an unknown number of other officers, but those have not been disclosed because they are protected by the privacy act.
Release of the investigation's results has been delayed for months. The probe was completed and the punishments delivered by August. Families of the three soldiers were given unclassified briefings on the results of the investigation later last year. According to a military official, part of the delay was due to legal reviews and the movement of the units involved out of Iraq.
In the rape-killing case, five soldiers were charged in the March 12, 2006, incident. Three have entered guilty pleas, one soldier's trial has been delayed and the fifth is being prosecuted in federal court because he had already left the military when he was charged.
Meanwhile, the massive search for three U.S. soldiers feared captured by al Qaeda entered its sixth day Thursday.
The military said the still-unknown militants who ambushed their convoy apparently confiscated the dog tags of one of the four American soldiers who died in the attack.
Maj. Webster Wright, a spokesman for the Second Brigade of the 10th Mountain Division, the unit that was attacked and that is leading the search, said Saturday's assault in an insurgent stronghold south of Baghdad apparently used rocket-propelled grenades and small arms fire to severely damage the two Humvees in the stationary U.S. convoy.
He said the dog tags of one of the four American soldiers who died were missing and apparently had been taken from the scene by the attackers. That could explain why the military has only been able to identify three of the four dead U.S. soldiers.
The Army has identified Pfc. Joseph Anzack and Spc. Alex Jimenez as two of the missing soliders. The third missing troop's name has not yet been released.
Maj. Gen. Rick Lynch, commander of U.S. troops south of Baghdad, said Wednesday that the U.S. was offeringfor information on the missing soldiers' whereabouts.
"We've done so much as to drain canals after a report that the bodies were in a canal," Lynch told The Associated Press. "So we're leaving no stone unturned."
Lynch said he was optimistic that the three soldiers would be found alive, and the search remained focused on the area where they went missing in a rural area near the town of Youssifiyah, 12 miles south of Baghdad.
An al Qaeda front group, the Islamic State of Iraq, has said it captured the U.S. soldiers and warned the Americans in a Web statement on Monday to call off the hunt "if you want their safety."