Relatives of a 14-year-old Iraqi schoolgirl who was raped and murdered by a US soldier yesterday called for her killer to be executed after a Kentucky court found him guilty of the crimes.

Private Steven Green, now 24, was the ringleader of one of the most shocking atrocities committed by US forces following the 2003 invasion. The crime sparked a wave of protests by the Iraqi public, brought angry condemnation from the government, and aggravated tensions between Baghdad and Washington.

A group of soldiers from the 101st Airborne Division plotted the raid, at Green's instigation, over a game of cards and a session drinking whiskey. They donned black "ninja" outfits in an attempt to hide their identities and then broke into the family home of Abeer Qassim al-Janabi in Mahmudiya, 20 miles south of Baghdad.

Download the new Independent Premium app Sharing the full story, not just the headlines

The private, who was 19 at the time of the attack, shot Abeer's father, mother and six-year-old sister to eliminate witnesses, while two colleagues raped the girl in an adjoining room. According to his accomplices, Green then joined them and said with a laugh: "I have shot them all, they are all dead".

He went on to take his turn raping the schoolgirl before covering her face with a pillow and shooting her three times. The soldiers started to leave but paused to consider the corpse and after a discussion, decided to douse Abeer's body with kerosene and set it alight. The men then went back to base and celebrated with a barbecue.

Before the investigation began into the multiple killings. Green was "honourably discharged" from the army, having been diagnosed with a personality disorder. He was the first ex-soldier to be charged under a US law that allows prosecution for crimes committed overseas.

After more than 10 hours of deliberations, a Kentucky jury on Thursday found Green, who hails from Midland, Texas, guilty on 16 charges including rape, premeditated murder and obstruction of justice. The jurors will reconvene on Monday to decide the penalty for his crimes. Yesterday relations of the murdered Iraqi family said they would only be satisfied that justice had been done if Green was given a death sentence and it was carried out.

"So they decided this criminal was guilty, but we don't expect he'll be executed. Only if he's executed, will we know that the right thing was done," a cousin, Yusuf Mohammed Janabi, told Reuters. The dead schoolgirl's uncle, Karim Janabi, added: "By all measures, this was a very criminal act. We are just waiting for the court to sentence him so he gets justice and the court can change the image of Americans."

An AK-47 rifle, the usual weapon of choice for militants, was found at the al-Janabi house. And initially, the soldiers claimed that the attack had been carried out by Sunni insurgents. When local people disputed this, the story was changed to the family, who were Sunnis, being murdered by a Shia death squad.

Green, however, repeatedly spoke about killing Iraqis to avenge fellow American soldiers who had been killed in the area – the so-called "Triangle of Death" – in clashes with militants. He also boasted about what he had done saying the experience was "awesome", although he later maintained that he was not being serious.

Daily coronavirus briefing No hype, just the advice and analysis you need Enter your email address Continue Continue Please enter an email address Email address is invalid Fill out this field Email address is invalid Email already exists. Log in to update your newsletter preferences Register with your social account or click here to log in I would like to receive morning headlines Monday - Friday plus breaking news alerts by email Update newsletter preferences

What actually took place only emerged during a series of post-combat debriefings. At which point, an investigation was started by the military police. A few weeks after the killings in Mahmudiya, the mutilated bodies of two American soldiers were found in the area. A video showing the corpses was posted on a jihadist website with the message: "We present this as revenge for our sister who was dishonoured by soldiers of the same brigade. We have taken this revenge for the honour of our sister."

The cold-blooded brutality at Mahmudiya led to comparison with atrocities committed by US forces in Vietnam. The Iraqi events became the subject a film, Redacted, directed by Brian De Palma, which won an award at the Venice Film Festival. The production was, however, strongly criticised by some right-wing columnists and shock jocks for supposedly undermining American forces in Iraq and putting them in danger.

The Mahmudiya rape and murder came at a time of several controversial incidents of Iraqi deaths involving the US military and private security contractors. The Baghdad government demanded the right to try those responsible before Iraqi courts, but the call was rejected by Washington.

Green admitted participating in the killings at his trial before a federal court in Padukah. His defence team maintained that he was suffering from combat stress due to the deaths of comrades and in a confused state of mind, he could not tell the difference between friend and foe.

"You have to understand the background that leads up to this perfect storm of insanity," Patrick Bouldin, one of Green's defence lawyers, told the court. "They couldn't tell the village people and the farmers from the insurgents and the terrorists."

But prosecutors gave that explanation short shrift, saying that Green was predisposed to the crime. "Who could have done these things? It wasn't done by insurgents or terrorists. It was the work of this man, Steven Green," argued federal prosecutor Brian Skaret. "Steven Green wanted to kill Iraqi civilians ... he wanted to kill them all the time, nonstop."

The defence also claimed that correct procedures had not been followed in Green's discharge from the army, and that he had offered to re-enlist so he could be tried before a court martial like his accomplices and not in front of a civilian jury. His family said they believed that he would be less likely to face a death sentence from a military jury.

In August 2007, Private Jesse Spielman was convicted of conspiracy to rape and murder and sentenced to 110 years in prison for his role in the incident. Two other soldiers, Specialist James Barker and Paul Cortez were also convicted and are serving 90 years and 100 years respectively in prison. A fourth was sentenced to 27 months for his role as a lookout.

Darren Wolff, one of Green's defence lawyers, told the Associated Press: "Is this verdict a surprise to us? No. The goal has always been to save our client's life. And, now we're going to go to the most important phase, which is the sentencing phase and we're going to accomplish that goal."