Military investigators on Sunday began sifting through the rubble of two Black Hawk helicopters, seeking clues to whether a guerrilla attack, mechanical failure or pilot error caused Saturday's crash, which killed 17 soldiers -- the largest loss of life since the start of the war in Iraq.
The Army publicly held firm to its position that no definitive proof had emerged pointing to a hostile attack, despite persistent media reports citing military sources and eyewitnesses blaming enemy fire.
"If this either involved ground fire or there was a safety-related accident, we want to make sure we take all precautions so that it doesn't happen again," said Maj. Trey Cate, spokesman for the 101st Airborne Division, based here. "We're removing the debris and gathering up as much of the aircraft pieces as we can to be sure we have everything we need to do the investigation."
Among other clues, Cate said, the skin of the aircraft should show if it had been pierced by bullets, rockets, grenades or another weapon.
By midafternoon, troops had removed the bodies, gathered the debris and departed the crash zone, and there was no obvious sign of additional security measures or house-to- house searches for suspects.
Residents came into the streets to gawk at the places where the helicopters and debris had fallen to the ground.
The two UH-60 Black Hawks, among the 250 helicopters assigned to the 101st Airborne, crashed early Saturday evening in a heavily populated neighborhood of west Mosul, just as many residents were saying their Ramadan prayers. One Black Hawk came down atop a residence while the other broke into pieces over a school playground and a mosque, about 275 feet away from the other crash site.
Officials and residents were astonished that no one on the ground was hurt. Helicopter overflights are a regular part of life here.
"I can only say it was an act of God at Ramadan that my family was able to walk out alive," said Hashem Mohammed Hussein, a 30-year-old laborer and father of four whose home, with 10 people inside, was destroyed when one of the helicopters hit it. "This must be God's will."
Along with 17 dead, the crashes left five soldiers wounded.
The incident brought to five the number of Army helicopters that had plunged to the ground in a three-week period starting Oct. 25, taking 39 lives. Officials blamed enemy fire in the other crashes. The Army had no immediate plans to scale back helicopter flights, although some routes and schedules have been changed to reduce the risk of enemy fire.
Military officials have described the enemy's successes in destroying aircraft as more a matter of blind luck than skill or the impact of new weaponry.
Loyalists of the former regime thought to be directing the insurgency are known to have access to ample caches of ground-to-air-rockets, grenade launchers and other weaponry capable of downing helicopters.
Mosul, a city of more than 1.5 million people, was the base of a major division of Saddam Hussein's army.
Attacks against U.S. forces remain a daily fact of life here, though the number is well below that in the so-called Sunni Triangle to the south, the heartland of Hussein loyalists.
Those who claim to have witnessed Saturday's crash have given conflicting versions of the event. They include descriptions of direct missile hits on each copter and a midair crash after one chopper took evasive action to avoid ground fire. But authorities have dismissed much of the testimony as imaginary, exaggerated or politically tainted.
One official said a midair collision was the most likely scenario, given the proximity of the two sets of debris. But explaining why the two copters had collided -- or appeared to be flying so close to each other, possibly in breach of guidelines -- remained difficult, he said.
Both copters were flying at night without lights, as is typical in Iraq. But the military said the pilots were qualified in limited-visibility flight operations with night-vision goggles.
At the time of the crash, the two aircraft had different tasks. One was transporting 10 troops back to base; the other was carrying a 12-member quick-reaction team, a kind of emergency squad to respond to urgent situations such as attacks against coalition forces.
The Black Hawk carrying the response team was believed to have been called to an incident in which shots were fired from a passing vehicle at U.S. troops guarding a bank. One shoulder was hit in the leg. The drive-by vehicle got away, despite intensive return fire.
Whether gunmen in that incident opened fire on the arriving helicopter had yet to be determined, one official said. It is possible that gunfire caused the pilots to lose control of the Black Hawk and somehow veer into the other copter, the official said, stressing that this was only a theory at this point.
The helicopter carrying the quick-reaction force is the one that crashed into Hashem Mohammed Hussein's three-story home, punching a hole in its roof, knocking down an exterior wall and causing a fire that consumed much of the dwelling.
Of the dozen soldiers aboard, seven were killed and five survived, the latter pulled from the wreckage by rescuers that included Mosul police and fire units.
Two blocks away, pieces of the second Black Hawk were gathered and assembled atop a flatbed truck. All 10 soldiers aboard that helicopter perished.
At the Hussein house, relatives said they were not angry at the U.S. government for the destruction its aircraft had visited upon their home.
"These men were doing their job," Hussein said as he stood on the second floor, below a gaping hole in the steel-reinforced roof.
But family members said they would gladly accept the compensation money that, they said, U.S. officers vowed was forthcoming. The amount is not yet clear, but relatives said it should be paid in dollars and adjusted for the inflationary times of the new Iraq. "I have no hard feelings against the Americans, as long as they pay us the compensation that they owe us," said Mohammed Hussein, the 61-year-old family patriarch, after he finished his afternoon prayers in the shaded backyard of a neighbor's home.