On a hot August afternoon exactly three years ago Bassam Aramin was adamant that he did not want revenge for the death of his ten-year-old daughter, Abir, but justice. At the time, he added quietly: "I have to prove my daughter was killed: that is my problem."

Yesterday he had the satisfaction of knowing that his three-year fight to do just that had been vindicated by a judge's ruling that Abir Aramin had indeed been shot dead by a border policeman with a rubber bullet, that the killing was "totally unjustifiable" and that the state should pay her family compensation.

It had not been easy. Abir, described by teachers as a "lovely" model student, was fatally wounded in January 2007 as she walked down the street with her sister and two friends after buying sweets in a shop across the road from her school in the West Bank village of Anata at the end of a maths exam.

The dead girl's father spoke eight months later to The Independent after learning that police investigators had closed the file on his daughter's death without attributing blame for it.

He described how his wife, Salwa – who, like him, was always convinced she had been killed by a police rubber bullet – had broken down in tears when she heard that there was to be no prosecution, feeling "that they had killed her another time".

Then, when he and the Israeli human rights organisation Yesh Din contested the police decision in the High Court, it refused to re-open the case on the grounds that she could have been killed by a stone thrown by Palestinian rioters.

The family's subsequent civil suit succeeded this week when Jerusalem District Judge Orit Efal-Gabai declared unequivocally in open court: "Abir and her friends were walking down a street where there were no rock-throwers, therefore there was no reason to shoot in their direction.

"It is clear that Abir's death, caused by a rubber bullet shot by border guards, was due to negligence..."

Quietly spoken as ever, Mr Aramin said yesterday that his wife had cried again when she heard the news of Monday's ruling, but this time from relief that the truth had been established at last. He said that his court victory was "historic" and was "a really very important message: don't give up. If you believe in justice, even under the occupation, don't give up for one second".

Mr Aramin's determination to pursue every avenue, whatever the obstacles, in the Israeli legal system is at one with a personal philosophy forged by an unusual life story. A one-time Fatah militant who was gaoled for seven years for an attack on an Israeli Army jeep, Mr Aramin renounced violence and became, in time, a prominent member of two remarkable cross-community organisations.

One was Combatants for Peace, which he helped to found and in which former Palestinian gunmen and ex-Israeli soldiers meet to share their experiences and campaign for an end to the occupation by peaceful means; and the other – which he joined after Abir's death – was the Bereaved Families' Circle, which brings together families of Palestinians killed in Israeli military operations with those of Israeli victims of Palestinian militant attacks, including suicide bombings.

Underlining his belief that the alternative to the legal route was acts of revenge which perpetuated the cycle of violence and did nothing to prevent further deaths of children like Abir, he cited the reaction of his son, Arab. "This was very important for me first of all to protect my son. He wanted to avenge his sister's blood. It's very difficult to convince a 15 year old that there should not be revenge."

He said the Palestinian attitude to Israeli security forces after such attacks had too often been in the past: "You kill children, no one punishes you. You don't feel you did a crime. We will continue to be silent or we will think of revenge."

Abir's friend, Abrar Abu Qweida, who was 12 at the time and who gave evidence in the court hearing which ended this week, told The Independent less than a week after the shooting how the group had been walking down the hill outside the school after leaving the shop.

While three or four boys were throwing stones from a distance at the bottom of the hill, she noticed a gun protruding from the back of an Israeli jeep which had passed the girls, going in the opposite direction. It was then that Abir had been shot in the back of the head at a range of about 30 metres.

Mr Aramin says that he could not have gone on with the legal fight without the continued "love and support" of his friends – Israeli as well as Palestinian – in the two organisations.

An Israeli writer, David Grossman, was among supporters who turned up at a separate Supreme Court hearing over a demand for the police investigation to be reopened into Abir's death. The court has demanded a state justification of the decision to close the investigation, which is now expected in October.

Mr Aramin – speaking yesterday in his mother's home town of Halhoul – remains determined that the man who shot his daughter should be brought to trial. He is convinced he knows which of the policemen he saw during the recent hearing was responsible.

Mr Aramin says he accused him outside the court. When the man denied any responsibility, he said: "I said I wish you a long and healthy life but also for your conscience to wake up. I am sorry but I will follow you until there is justice."

Despite scepticism among both his Palestinian and Israeli friends he was always convinced – despite the setbacks – that he would eventually "win with reason".

"My case is not a political one – I don't want to punish the policeman who killed my daughter because he is Israeli but because he killed a child."

Palestinian child victims

* Ahmed Khatib, aged 12 and believed to have been holding a toy gun at the time, was shot during a raid by the Israeli army in 2005. He died in an Israeli hospital, and his parents donated his organs, even though they would go to Israeli patients. This act, which benefited six people, inspired German filmmaker Marcus Vetter to make the documentary Heart of Jenin.

* Mayar and Aya Abuelaish, aged 15 and 13 respectively, were killed during the Israeli offensive on the Gaza strip in 2008-9. Their father, Izzeldin Abuelaish, had broadcast live reports about the impact of the war before the family home was hit. The girls' 20-year-old sister, and 17-year-old cousin also died.