It was after midnight, and the teenage Iraqi boy was home with his older sister in a battered concrete apartment. Neighbors say he heard kicks at the door and thought thieves were trying to break in.
So Haroun Fadhil took an assault rifle - one per family is permitted by US authorities for self-defense - and fired off several bullets.
But the intruders were not thieves. They were soldiers from the US Army's 82nd Airborne Division, who say their inquiries at a nearby pool hall about "bad guys" prompted an Iraqi to lead them to the Fadhil's door.
No one disputes these facts, that two Iraqis died and four US soldiers were injured. Beyond that, the US and Iraqi versions of what took place differ markedly, reflecting parallel realities that often erode trust as the US attempts to win Iraqi hearts and minds.
The result, according to Iraqis here: two dead civilians, six apartments shot up, and anger welling up toward American forces among some residents of Building 198, who say the predawn violence was a tragic overreaction.
The result, according to US soldiers on the scene: four wounded Americans; a trove of ammunition and pro-Saddam, anti-US propaganda; and an operation that was "by the book."
Qais Ismael, a neighbor in the rundown complex, says that while Iraqis are still on America's side, more incidents like this could change that.
"This American attitude, if they keep going with it, may make people angry and make them resist," says Mr. Ismael. "We don't want them to push us, so that we will all be resisters."
There is no shortage of lethal incidents involving US raids and patrols. But almost five months after the fall of Baghdad, troops have orders to work with Iraqis to forge a kinder, gentler occupation.
Coming to grips with insecurity, and an average of 15 attacks a day on coalition troops, though, has put some units on edge. The squad that moved in on the Fadhil apartment, from the Bravo Company, 3rd Battalion, 505th Parachute Infantry Regiment out of Fort Bragg, N.C., arrived just three weeks ago.
Officers deny using heavy-handed tactics in this case. Though they were not patrolling with an interpreter or a member of the Iraqi police - precautions that US units regularly employ, to help explain their aims to Iraqis - this unit says it used an "appropriate" degree of force, and when not under fire, reverted to a softer "knock and talk" approach.
The soldiers say they shouted "US Army! US Army!" at the door as they knocked, then began receiving fire through the door "instantaneously."
"If you knock on the door and people shoot, there is not much left to talk about," says 1st Sgt. Wylie Hutchinson, who was on the patrol. "Nobody in this unit wants to see dead people - we're here to help ... [and performed] exactly the same as any 82nd Airborne company would do on month No. 1, or month No. 12."
Events that night took a turn for the worse, however, when a massive explosion took the life of Haroun Fadhil's 18-year-old sister, Farah. Each side tells a different story.
Contrary to the US account, Iraqi neighbors insist that Farah was still alive when they extracted her from the kitchen after the blast, and that the Americans prevented them from taking her to the hospital for three hours, causing her to bleed to death. They say the blast was from a US grenade.
Iraqis say the other fatality, Marwan Hassan, was shot outside while he was searching for his brother. He ran away, they say, despite orders to stop.
The Americans say Farah was dead when they found her in the kitchen, and that she had a AK-47 assault rifle with her. Besides anti-US and pro-Saddam leaflets, they say they found at least two assault rifles, bandoliers of bullets, and four empty rifle magazines with 50 to 60 empty bullet casings.
"There was never a problem. Coalition troops used to play with the children and exchange sweets and sandwiches and watermelon," says Ali Abdul Hussein, whose front door is a few feet away, directly across from the Fadhil's. "People used to respect them because they kept the peace. But what happened the other night was different. It was very firm, and made people afraid."
The heavyset Mr. Hussein was himself arrested and held for three days; the cuts on his wrists from the tightly bound plastic cuffs are still raw. US troops say they found quantities of pro-regime material in his house, a detail that Hussein did not offer during an interview.
While troops confirm they used a percussion grenade, they say that the second large explosion that blew up the apartment and killed Farah was sparked by a burning tracer round - American or Iraqi - that hit a leaking propane tank.
US medics at the scene treated 16-year-old Haroun for burns. But while they evacuated their own burn victims, the unit came under small arms fire either from the roof or a high window above, says 1st Sergeant Hutchinson.
For some Iraqis, US troops overreacted. "So there were some gunshots - so what?" says a senior police officer familiar with the incident, who asked not to be named. "There were 1,000 ways to convince the boy to come out."
The soldiers dispute that claim, saying there was no time. "We returned fire at just the right level to gain control of the situation," says Capt. J.C. White, the company commander. Iraqi criticism over the incident "does surprise me a bit," Captain White says, "but they don't have all the facts."
Still, the US officers say that their reception after the incident has been far less hostile than they expected and sometimes has been more welcoming. Several Iraqis have told them that they indeed hit the neighborhood Baathists.
In fact, while the Iraqis portray their neighborhood as peaceful, the Americans say they hear gunfire every 15 to 20 minutes while on night patrol in the area. That night, they had already confiscated two machetes from men and several rocket-propelled grenades and sniper scopes from a house. Three or four gunmen had fired on a similar patrol three days earlier, less than 500 yards from Sunday's target apartment.
"We didn't hear any warning from the Americans, we didn't know the coalition was searching - we didn't know anything because we were sleeping," says Hussein, with the torn wrists. If they let us live in peace, we will live in peace. We don't hate them. Our country loves America."