Nineteen-year-old Yousra al-Azam and her fiancÚ had spent the afternoon shopping for her wedding dress in Gaza City.
By Alan Johnston
BBC News, Gaza
Palestinian youth watch the sunset from the Gaza Strip's beach
Later they went down to the beach. They took something to eat and drink, and they sat and watched the waves.
Yousra's marriage was supposed to be in just a few days time.
But as it turned out, that evening on Gaza beach was to be her last - and it was about to end in terrible violence.
On her way home to Beit Lahiya after dark, her car was pulled over by a vehicle full of masked men.
Also in the car with Yousra and her partner were another couple - her sister, Magdoleen and her fiancÚ.
"The men were holding weapons and clubs," said Magdoleen. "The moment I saw them they started shooting into the car."
"They opened the doors and started beating us. I got out and escaped, but one of them followed me and kept beating me and beating me. He threw me on the ground and beat me with a club."
"People in the street tried to stop him, but he had a weapon and he warned them that if they stepped forward they would be shot."
Calls for justice
Yousra al-Azam was killed in the attack. Shot dead.
The gunmen were members of the Islamist militant movement, Hamas.
Witnesses said the men claimed to be a squad "morality police".
Yousra al-Azam's relatives want her killers to be brought to book
It seems that - in the eyes of the gunmen - something in the behaviour of the couples had been deemed unacceptable in Islamic terms.
Yousra's family say she had done absolutely nothing that deserved criticism of any kind - let alone a deadly assault.
Two of the attackers have been arrested, but three others are still on the loose.
Yousra's relatives say that Hamas must do nothing that stands in the way of them being caught, put on trial and executed.
Within Gaza - in comparison with other armed groups - Hamas has a reputation for discipline and organisation.
And there is some surprise here that it was Hamas men who carried out the attack.
"Hamas must implement God's law on its members and deter them," says Yousra's uncle, Ramadan.
Hamas says it preaches morality but does not pass judgement
"If the situation continues in this way, Hamas' reputation will be damaged."
The organisation is scrambling to limit this damage.
"These were members of Hamas but they acted as individuals," said Mushir al-Masri, a Hamas spokesman.
"It was an irresponsible act, and it was against the policy of Hamas."
"We are in favour of implementing the law, and this is now a matter for the Palestinian Authority. We will not hide anyone. We want an open investigation."
Mr Masri denied that Hamas had set up any vigilante-style, "morality police" squads.
He was asked if the killing might be the result of Hamas giving young men weapons, and then preaching to them what many people would regard as quite extreme notions of Islamic morality.
"Firstly, it may not have been Hamas weapons that were used," Mr Masri replied.
"And secondly we talk about morality openly through the mosques and our public rallies because this message is one of the best things about our religious aims."
"But at the same time we don't consider ourselves as sitting in judgement over the people."
The death of Yousra el-Azam has been a particularly shocking example of the lack of law and order that deeply concerns many Palestinians.
They've watched their society grow increasingly anarchic in the course of their uprising against Israel.
A leading Palestinian psychologist and political analyst, Dr Eyad el-Surraj, blames the lack of a strong central authority in Gaza.
"Authority is being taken away sometimes by individuals - some of whom feel that they are the guardians of morality in society," says Dr Surraj. "It's due to the absence of the rule of law."
Dr Surraj says that the stress and pressure of decades of Israeli occupation lie at the root of many of the serious social tensions here.
But Palestinians also believe that their leaders could do much more to restore order.
And the calls for action can only grow louder after the killing of the young woman on the road to Beit Lahiya.