ANOTHER jihad atrocity has left behind a trail of bodies and, as so often, the question: how can a seemingly ordinary young person end up as a fanatic in such a murderous organisation?
Samantha Lewthwaite's journey took her from the generally peaceful Co Down town of Banbridge to the group that inflicted such carnage at Westgate Shopping Centre in Nairobi. Along the way she was transformed from schoolgirl to "White Widow".
Whether or not she was actually in the mall when her colleagues opened fire so callously on shoppers, she was one of the group's most committed activists and so almost certainly had a hand in planning the massacre.
Her life has thus been marked by at least two bloodbaths, the first being the work of her husband, Jermaine Lindsay. He was the suicide bomber whose device killed 26 people in the explosion at London's King's Cross tube station in 2005.
The Kenyan authorities have also linked her to various other violent incidents in recent years – so many, in fact, that she has achieved almost mythical status in the extremist world she chose to inhabit.
She is said – probably with some exaggeration – to be an expert in bomb-making, sniping, organisation, planning and training.
In Banbridge, her 85-year-old grandmother Elizabeth Allen – who was given a panic alarm by the security services in case Lewthwaite tried to contact her – has been taken to hospital suffering from stress caused by the global publicity attracted by her granddaughter.
According to her father Andrew: "I cannot believe she would be involved in something like this. I haven't spoken to her for a long time."
Andrew Lewthwaite was a soldier who married a Co Down Catholic, Christine Allen, while serving in Northern Ireland in the 1970s. The family lived in Banbridge for a time before moving, while Samantha was at primary school, to Aylesbury in Buckinghamshire. Her parents separated in 1995.
The girl, who had taken an interest in religion, converted to Islam in her mid-teens, switching to Islamic dress and wearing the hijab, a garment that covers the head and chest.
She was described by Councillor Raj Khan, who knew her family in Aylesbury, as "an average, British, young, ordinary girl". "She had a very great personality," he recalled.
"I knew her when she was a child – she was very innocent, lacking confidence, shy and very easy to get on with. She was a follower, not a leader.
"She was not strong-headed – that's why I find it absolutely amazing that she is supposed to be the head of an international criminal terrorist organisation."
Novid Shaid, a teacher at a college she attended, added: "She seemed to be really proud wearing the hijab.
"After a few years we noticed her wearing the full galabiya (full-length robe), which some converts tend to do when they become more serious."
She developed a commitment not just to religion but to violent extremism when she had contact with a radical preacher and then married Lindsay, whom she had met on an Islamic chatroom.
She later explained: "I just wanted to find a Muslim husband and settle down. When we got together we were fantastic and prayed five times a day together."
They started a family, and in fact she was seven months pregnant when he detonated the bomb which killed him and made her a widow.
When he died, she pretended to be ignorant of his activities, telling a newspaper: "How these people could have turned him and poisoned his mind is dreadful. "He was an innocent, naive and simple man – I suppose he must have been an ideal candidate."
Not long after the attack she disappeared off the radar screen and moved to Africa.
There was no public sign at that stage that the British security services suspected her of involvement in her husband's activities.
In Africa she married again, but her second husband was killed in an internal dispute. Becoming steeped in al-Shabab activities, she was suspected of involvement in attacks on hotels, bars and other centres which attracted western visitors in Kenya.
She was reportedly linked to Jermaine Grant, who is regarded as a suspected British Islamist militant with alleged links to al-Qa'ida.
He is currently on trial in Kenya for possession of explosives, chemicals and switches which could be used to make a bomb.
She has a history of using forged passports and it was alleged she was posing as a South African called Natalie Faye Webb last year.
Lewthwaite, who now has three children, was already being sought by police in a number of African countries before the Westgate attack.
The carnage there means she has achieved a new status, as one of the world's most dangerous women.