Leila Hussein lived her last few weeks in terror. Moving constantly from safe house to safe house, she dared to stay no longer than four days at each. It was the price she was forced to pay after denouncing and divorcing her husband - the man she witnessed suffocate, stamp on, then stab their young daughter Rand in a brutal 'honour' killing for which he has shown no remorse.

Though she feared reprisals for speaking out, she really believed that she would soon be safe. Arrangements were well under way to smuggle her to the Jordanian capital, Amman. In fact, she was on her way to meet the person who would help her escape when a car drew up alongside her and two other women who were walking her to a taxi. Five bullets were fired: three of them hit Leila, 41. She died in hospital after futile attempts to save her.

Her death, on 17 May, is the shocking denouement to a tragedy which had its origins in an innocent friendship between her student daughter, Rand Abdel-Qader, 17, and a blond, 22-year-old British soldier known only as Paul.

The two had met while Rand, an English student at Basra University, was working as a volunteer helping displaced families and he was distributing water. Although their friendship appears to have involved just brief, snatched conversations over four months, Rand had confided her romantic feelings for Paul to her best friend, Zeinab, 19.

She died, still a virgin, four months after she had last seen him when her father, Abdel-Qader Ali, 46, discovered that she had been seen talking 'to the enemy' in public. She had brought shame on his honour, was his defence, and he had to cleanse his family name. Despite openly admitting the murder, he has received no punishment.

It was two weeks after Rand's death on 16 March that a grief-stricken Leila, unable to bear living under the same roof as her husband, found the strength to leave him. She had been beaten and had had her arm broken. It was a courageous move. Few women in Iraq would contemplate such a step. Leila told The Observer in April: 'No man can accept being left by a woman in Iraq. But I would prefer to be killed than sleep in the same bed as a man who was able to do what he did to his own daughter.'

Her words were to prove prescient. Leila turned to the only place she could, a small organisation in Basra campaigning for the rights of women and against 'honour' killings. Almost immediately she began receiving threats - notes calling her a 'prostitute' and saying she deserved to die like her daughter.

Even her sons Hassan, 23, and Haydar, 21, whom she claimed aided their father in their sister's killing, disowned her. Meanwhile, her husband, a former government employee, escaped any charges, and even told The Observer that police had congratulated him on what he had done.

It is not known who killed Leila. All that is known is that she was staying at the house of 'Mariam', one of the women's rights campaigners, whose identity The Observer has agreed not to reveal. On the morning of 17 May, they were joined by another volunteer worker and set off to meet 'a contact' who was to help Leila travel to Amman, where she would be taken in by an Iraqi family.

'Leila was anxious, but she was also happy at having the chance to leave Iraq,' said Mariam. 'Since the death of her daughter, her own life was at serious risk. And this was a great opportunity for her to leave the country and to fight for Iraqi women's rights.

'She had not been able to sleep the night before. I stayed up talking to her about her plans after she arrived in Amman. I gave her some clothes to take with her and she was packing the only bag she had. She was too excited to sleep.'

Mariam said that when she awoke Leila had already prepared breakfast, cleaned her house and even baked a date cake as a thank-you for the help she had been given. After the arrival of 'Faisal', the volunteer (whose identity is also being protected), the three left the house at 10.30am and started walking to the end of the street to get a taxi. They had walked less than 50 metres when they heard a car drive up fast and then gunshots rang out. The attack, said by witnesses to have been carried out by three men, was over in minutes. Leila was hit by three bullets. Mariam was hit in her left arm and Faisal in her left leg. 'I didn't realise I had been shot for a few seconds, because as I heard the gunfire I saw Leila falling to the ground and saw blood pouring from her head,' said Mariam. 'I was so shocked, I didn't immediately feel the pain.'

Two men ran from their homes to help. They rushed Leila to hospital and a passing taxi took the other two. But Leila died at 3.20pm, despite several operations to save her. As she lay in her own hospital bed receiving treatment, Mariam said that she heard someone saying that Leila had been shot in the head. But there were other mutterings that were clearly audible. 'I could hear people talking on the corridors and the only thing that they had to say was that Leila was wrong for defending her daughter's mistakes and that her death was God's punishment.

'In that minute I just had complete hatred in my heart for those who had killed her.'

Police said the incident was a sectarian attack and that there was nothing to link Leila's death to her family. 'Her ex-husband was not in Basra when it happened. We found out he was visiting relatives in Nassiriya with his two sons,' said Hassan Alaa, a senior officer at the local police station in Basra. 'We believe the target was the women activists, rather than Mrs Hussein, and that she was unlucky to be in that place at that time.'

It is plausible. Campaigners for women's' rights are not acceptable to many sections of Iraqi society, especially in Basra where militias have partial control in some districts and impose strict laws on locals, including what clothing they should wear and what religious practice they should follow.

Since February 2006, two other activists from the same women's organisation have been killed in the city. One of them was reportedly raped before being shot. The other, the only man working for the non-governmental organisation (NGO), and a father of five who was responsible for the organisation's finances, was shot five months ago.

There could be many with a grudge against such organisations. However, Mariam believes Leila was targeted, pointing out she had been hit by three bullets. 'When we were shot, they focused on Leila, not us,' she said.

Since the attack the NGO has stopped its work in Basra. 'We daren't answer the phones because we have received so many threats since we gave our support to Leila's case,' said Mariam. 'Most of our members are preparing to leave the city and even Iraq if they can raise the money.'

A single mother since her husband was killed for refusing to join a militia, she too intends to move when she can. Faisal, who also survived her injuries, is still suffering post-surgical infection. She preferred not to speak, but her mother, who wished to remain anonymous, said: 'My daughter is very shocked at what happened, and my two grandsons can't stop crying since they saw her in hospital.'

Leila's burial was arranged within hours of her death by the husband of one of her cousins and Mariam's father.

The Observer visited Rand's father and two brothers at their Basra home, but they refused to talk beyond Hassan proclaiming his father's innocence. When asked if he would be visiting his mother's grave, he shrugged: 'Maybe in the future.'

Leila was an orphan, raised by an uncle who died in the Shia uprising against Saddam Hussein in the early 1990s. Hamida Alaa, 68, a friend of the uncle, said: 'The poor woman was killed and now her name and history is buried with her. No one wants to speak about it. She is just one more woman killed in our country who has already been forgotten by the local society.'

In the last days of her life, Leila was suffering from the pressure of having gone against her husband. 'She was sleeping with the help of sedatives,' said Mariam. 'She would wake up at night with terrible nightmares, even dreaming of being suffocated as her daughter was. She had been threatened so many times and that's why she was so scared. Her indignation over Rand's death is what led her to her own coffin. Their history ends here. But Leila was a hero. A woman who was strong enough to say no to Iraqi men's bad attitudes. Sadly most Iraqi women do not have the same strength and they will stay in their homes.'

Mariam has moved out of her home. But within hours of speaking to The Observer a close friend went to her new address to deliver a message that had been left for her at her front door. It read: 'Death to betrayers of Islam who don't deserve God's forgiveness. Speaking less you will live more.' She believes it was sent by Leila's killers.

'They want this story to be buried with Leila,' she said. 'But I cannot close my eyes to all this.'