Police hunting for the White Widow Samantha Lewthwaite fear she is planning more deadly attacks aftermasterminding the Nairobi shopping centre massacre.
It has been revealed that documents found on her laptop show the British terror suspect had been plotting to target a mall in Kenya’s capital for at least two years.
Officers say files on the computer clearly show her relentless quest to commit mass carnage and that she has the funds and knowledge to carry it out.
She has fuelled her obsession by studying writings that advocate the cold-blooded killing of women and children.
A source said: “The international security community is working round the clock to identify her whereabouts and capture her without delay.
“The lives of hundreds, if not thousands, of innocent people are at risk if she is able to launch an attack. She needs to be stopped in her tracks before it is too late.
"She is a danger to the world.”
Police seized the laptop in Kenya in 2011 – along with other damning evidence including a sickening diary – though Lewthwaite was somehow allowed to slip through their fingers.
The computer showed how Lewthwaite had carried out painstaking research on how to make bombs and explosives.
But officers think that back in 2011 she had probably been plotting to attack a different mall from the Westgate shopping centre where al-Shabaab terrorists murdered at least 67 people, including six Britons, during the horror siege last month.
The security source said: “We have credible intelligence suggesting Samantha Lewthwaite was planning to murder innocent people in a Nairobi shopping mall.
“It appears her goal was to wreak havoc by detonating a bomb and it looks like she unfortunately came back to achieve her objectives with the Westgate attack.
“There should be no doubt that we are dealing with one of the most dangerous terror suspects in the world.
“Samantha Lewthwaite’s position within the terror group al-Shabaab has become highly significant.
“Her movements over the past two years have shown she has control over large amounts of cash, access to weapons and the detailed knowledge to make sophisticated and devastating explosive devices.
“Her central ideology to wage war in the name of Jihad is of grave concern. She has demonstrated she is devoted to committing murder and causing mayhem wherever she goes and is grooming her children to become killers.
“Lewthwaite is believed to be linked to at least six terror attacks and has been identified as having a major hand in the devastating Westgate siege in Nairobi.”
Samantha Lewthwaite
Interpol/PA
Lewthwaite, 29, who is nicknamed White Widow because she was married to 7/7 suicide bomber Jermaine Lindsay, has been dubbed the world’s most wanted woman after the Westgate atrocity.
She has been in hiding since December 2011 after police linked her and fellow Briton Jermaine Grant, 30, to a foiled bombing plot against Western tourists in Kenya.
Police interviewed her at the house of a known al-Qaeda operative in the Kenyan city of Mombasa, but failed to realise who she was.
Grant, from Newham, East London, was arrested and is now awaiting trial but Lewthwaite managed to flee hours after officers spoke to her. In her haste she left behind the trail of clues including the laptop.
Detectives also found a stash of ammunition.
Lewthwaite – using the alias Natalie Faye Webb – had rented at least three houses in Nairobi and Mombasa to plot terror attacks.
The mum-of-four paid a year’s rent up front for each property for the whole of 2011. Security sources say this shows how Lewthwaite, the daughter of an ex-British soldier, had become a major player in al-Shabaab with access to safe houses and “vast sums of cash”.
Details on the computer revealed she moved into a smart gated development in the upmarket Lavington area of Nairobi in around March 2011.
The plush flat is directly behind a shopping mall called The Junction.
As she studied the rantings of clerics who promote killing non-Muslim children, Lewthwaite was happy to try to persuade her own kids into the deluded holy war.
Her diary, entitled I Want To Be A Mujahid, showed she had begun grooming her children to emulate her first husband Lindsay, who was 19 when he murdered 26 people on the London Underground in 2005.
Lewthwaite, from Aylesbury, Bucks, had two children with Lindsay, and two who are thought to be the result of a relationship with London-born terrorist Habib Saleh Ghani. Women and children were among those shot dead in the al-Shabaab attack on the Westgate mall.
The White Widow was made the subject of a high-alert Red Notice by Interpol after being linked to the massacre.
Police sources have revealed for the first time that there is “specific intelligence” that puts Lewthwaite at the heart of at least six separate bomb plots in Kenya.
One was a grenade attack on a sports bar in Mombasa last year when a little boy was killed.