Officials are investigating whether a female British terror suspect nicknamed the "White Widow" could have been linked to the terrorism massacre in Kenya.

Witness accounts have suggested a woman was among the attackers in the Westgate Mall in Nairobi.

This has fuelled speculation that wanted Samantha Lewthwaite, who was married to July 7 bomber Jermaine Lindsay, was involved.

She is wanted by Kenyan police over links to a suspected terrorist cell planning bomb attacks.

samantha lewthwaite

Lewthwaite grew up in Buckinghamshire

On Monday morning, Kenyan police said most hostages had been rescued, but gunfire continued to be heard from inside the complex.

The death toll increased to 69, with 63 people missing.

In March 2012 it was reported that Lewthwaite, 29, who is originally from Aylesbury, Buckinghamshire, had fled across the border from Kenya to Somalia.

A Foreign Office spokesman said: "We are aware of the reports and we are looking into them."

The spokesman added: "It is really difficult to substantiate. We are looking at the names and seeing what we can find out."

Lewthwaite is a key member of al-Shabaab, the Mirror reported.

She grew up in suburban Buckinghamshire, and "stood out" as a Muslim convert at her school in Aylesbury, the BBC reported in 2012.

A Twitter account purporting to be an al-Shabaab spokesman named a 24-year-old man from London as one of the gunmen.

The @hsm_press2 account listed a string of names it claimed were involved in the attack before being closed down, as previous usernames linked to the terrorist group had been.

One of those murdered in the attack was award-winning British-Australian architect Ross Langdon and his Harvard-educated pregnant partner, Elif Yavuz.

The Telegraph reported that the couple, who were based in the east of the country had travelled to Nairobi for its superior medical facilities. Langdon, born in Tasmania, had designed buildings across Africa, including a hospital pro-bono and an eco-village in Uganda, and his partner Dr Yavuz worked for the Bill and Melinda Gates Foundation in Kenya.

Tributes poured in from friends and colleagues on social media:


Simine Alam
dear Ross Langdon and family. I feel blessed to have met you.


THEJUGERNAUTS
Just found out a good mate and great human being Ross Langdon was killed in terrorists attacks jn nairobi on the weekend. Saddened.

Friend Peter Adams wrote on his blog: "He was a much loved local lad. He was a colleague and friend who went out into the world as an architect doing wondrous things. Yet Ross always returned to his family and cultural roots here on the Tasman Peninsula and we all took immense pride in both his architectural abilities and his very generous, positive, and loving personality.

"There just was no dark side to Ross that I ever saw in the twenty or so years I knew him."

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  • Relatives help a woman at the Nairobi City Mortuary after she identified the body of a victim of the mall attack in Kenya, Sunday, Sept. 22, 2013. Kenyan authorities said Islamic extremist attackers remain inside the upscale Kenyan shopping mall, holding an unknown number of hostages, after killing at least 39 and injuring 150 during Saturday's attack. (AP Photo/Khalil Senosi)

  • Sunday, Sept. 22, 2013: Nairobi, Kenya_ Relatives help a woman at the Nairobi City Mortuary after she identified the body of a victim of the Saturday attack at a mall. Kenyan authorities said Islamic extremist attackers remain inside the upscale Kenyan shopping mall, holding an unknown number of hostages, after killing and injuring scores of people in the attack. An assault by Islamic extremists at a Kenya mall, a suicide attack on a Pakistani church and assaults by suicide bombers targeting mourners at Shiite and Sunni funerals in Iraq have killed more than 250 people and injured at least 470 others since Saturday. (AP Photo/Khalil Senosi)

  • Saturday, Sept. 21, 2013: Nairobi, Kenya_ A security officer helps a wounded woman outside the Westgate Mall after gunmen opened fire and threw grenades. Kenyan authorities said Islamic extremist attackers remain inside the upscale Kenyan shopping mall Sunday, holding an unknown number of hostages, after killing and injuring scores of people the attack. (AP Photo/Khalil Senosi, File)

  • Saturday, Sept. 21, 2013: Nairobi, Kenya_Civilians who had been hiding during a gun battle hold their hands in the air as a precautionary measure before being searched by armed police leading them to safety, inside the Westgate Mall. Kenyan authorities said Islamic extremist attackers remain inside the upscale Kenyan shopping mall Sunday, holding an unknown number of hostages, after killing and injuring scores of people in the attack. (AP Photo/Jonathan Kalan, File)

  • Kenya security forces are seen behind a wall outside the Westgate Mall in Nairobi, Kenya Monday morning, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff that killed at least 68 people and injured 175. (AP Photo/Jerome Delay)

  • Kenya security personnel, one in plain clothes, take cover outside the Westgate Mall in Nairobi, Kenya, Monday Sept. 23, 2013 after shooting started inside the mall. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff that killed at least 68 people and injured 175. (AP Photo/Sayyid Azim)

  • Kenya security forces are seen behind a wall outside the Westgate Mall in Nairobi, Kenya Monday morning, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff that killed at least 68 people and injured 175. (AP Photo/Jerome Delay)

  • Kenya security personnel arrive in a land rover outside the Westgate Mall after firing started inside the mall in Nairobi, Kenya, Monday, Sept. 23, 2013. Kenya's military launched a major operation at an upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during a two-day standoff that killed at least 68 people and injured 175. (AP Photo/Sayyid Azim)

  • Kenya Security personnel take cover outside the Westgate Mall after firing started inside the mall early Monday morning, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff that killed at least 68 people and injured 175. (AP Photo/Sayyid Azim)

  • Kenyans wait to donate blood for victims in Sunday's terrorist attack on a shopping mall, at Uhuru Park in Nairobi, Kenya Monday, Sept. 23, 2013. Hostages being held by al-Qaida-linked terrorists in the mall have not been released despite an earlier statement from the military that "most" had been rescued, a person connected to the situation told The Associated Press on Monday. (AP Photo/Khalil Senosi)

  • People donate blood for injured persons in an attack at the Westgate Mall, at Uhuru Park in Nairobi, Kenya, Monday, Sept. 23, 2013. Hostages being held by al-Qaida-linked terrorists in the mall have not been released despite an earlier statement from the military that “most” had been rescued, a person connected to the situation told The Associated Press on Monday. Military helicopters circled over the mall at daybreak, when about five minutes of sustained gunfire broke out at the mall, a clear indication that at least one of the estimated 10 to 15 gunmen who attacked the mall when it was filled with shoppers Saturday was still on the loose. (AP Photo/Khalil Senosi)

  • People donate blood for injured persons in an attack at the Westgate Mall, at Uhuru Park in Nairobi, Kenya, Monday, Sept. 23, 2013. Hostages being held by al-Qaida-linked terrorists in the mall have not been released despite an earlier statement from the military that “most” had been rescued, a person connected to the situation told The Associated Press on Monday. Military helicopters circled over the mall at daybreak, when about five minutes of sustained gunfire broke out at the mall, a clear indication that at least one of the estimated 10 to 15 gunmen who attacked the mall when it was filled with shoppers Saturday was still on the loose. (AP Photo/Khalil Senosi)

  • Stephen, center, who lost his father in Saturday's attack at the Westgate Mall in Nairobi, Kenya, is comforted by relatives as he waits for the post mortem exam at the city morgue Monday, Sept. 23, 2013. Islamic extremist gunmen lobbed grenades and fired assault rifles inside Nairobi's top mall Saturday, killing dozens and wounding over a hundred in the attack. Early Monday morning gunmen remained holed up inside the mall with an unknown number of hostages. (AP Photo/Jerome Delay)

  • Stephen, center, who lost his father in Saturday's attack at the Westgate Mall in Nairobi, Kenya, is comforted by relatives as he waits for the post mortem exam at the city morgue Monday, Sept. 23, 2013. Islamic extremist gunmen lobbed grenades and fired assault rifles inside Nairobi's top mall Saturday, killing dozens and wounding over a hundred in the attack. Early Monday morning gunmen remained holed up inside the mall with an unknown number of hostages. (AP Photo/Jerome Delay)

  • Paramedics and police officers run outside the Westgate Mall in Nairobi after heavy shooting started Monday, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff. (AP Photo/Sayyid Azim)

  • Armed police from the General Service Unit take cover behind a wall during a bout of gunfire, outside the Westgate Mall in Nairobi, Kenya Monday, Sept. 23, 2013. Hostages being held by al-Qaida-linked terrorists in a Nairobi mall have not been released despite an earlier statement from the military that "most" had been rescued, a person connected to the situation told The Associated Press on Monday. (AP Photo/Ben Curtis)

  • People take cover outside the Westgate Mall in Nairobi after heavy shooting started Monday, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff. (AP Photo/Sayyid Azim)

  • A paramedic runs for cover outside the Westgate Mall in Nairobi after heavy shooting started Monday, Sept. 23, 2013. Kenya's military launched a major operation at the upscale Nairobi mall and said it had rescued "most" of the hostages being held captive by al-Qaida-linked militants during the standoff. (AP Photo/Sayyid Azim)

  • A Red Cross assistant helps a child outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • A security guard helps a child outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • The mother and a security guard help a child outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • Security officers help a wounded woman outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • An injured person is helped on his arrival at the Aga Khan Hospital in Nairobi after an attack at the Westgate Mall, an upscale shopping mall in Nairobi, Kenya Saturday Sept. 21, 2013, where shooting erupted when armed men staged an attack. A witness to the attacks says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. Initial police reports had described the incident as a botched robbery. Witnesses say a half dozen grenades also went off along with volleys of gunfire in and around the mall. (AP Photo/Jason Straziuso)

  • An injured person is helped on his arrival at the Aga Khan Hospital in Nairobi after an attack at the Westgate Mall, an upscale shopping mall in Nairobi, Kenya Saturday Sept. 21, 2013, where shooting erupted when armed men staged an attack. A witness to the attacks says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. Initial police reports had described the incident as a botched robbery. Witnesses say a half dozen grenades also went off along with volleys of gunfire in and around the mall. (AP Photo/Jason Straziuso)

  • An injured person arrives at the Aga Khan Hospital in Nairobi after an attack at the Westgate Mall, an upscale shopping mall in Nairobi, Kenya Saturday Sept. 21, 2013, where shooting erupted when armed men staged an attack. A witness to the attacks says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. Initial police reports had described the incident as a botched robbery. Witnesses say a half dozen grenades also went off along with volleys of gunfire in and around the mall. (AP Photo/Jason Straziuso)

  • An injured person is helped on his arrival at the Aga Khan Hospital in Nairobi after an attack at the Westgate Mall, an upscale shopping mall in Nairobi, Kenya Saturday Sept. 21, 2013, where shooting erupted when armed men staged an attack. A witness to the attacks says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. Initial police reports had described the incident as a botched robbery. Witnesses say a half dozen grenades also went off along with volleys of gunfire in and around the mall. (AP Photo/Jason Straziuso)

  • An injured person makes a phone call as he is helped on his arrival at the Aga Khan Hospital in Nairobi after an attack at the Westgate Mall, an upscale shopping mall in Nairobi, Kenya Saturday Sept. 21, 2013, where shooting erupted when armed men staged an attack. A witness to the attacks says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. Initial police reports had described the incident as a botched robbery. Witnesses say a half dozen grenades also went off along with volleys of gunfire in and around the mall. (AP Photo/Jason Straziuso)

  • An armed police officer takes cover during a bout of gunfire outside the Westgate Mall in Nairobi, Kenya, Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Ben Curtis)

  • Armed police take cover behind escalators as smoke fills the air inside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • A body is seen on the floor, below right, as smoke fills the air inside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Civilians who had been hiding inside during the gun battle manage to flee from the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Armed police leave after entering the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Civilians who had been hiding inside during the gun battle manage to flee from the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • A woman who had been hiding during the gun battle runs for cover after armed police, seen behind, enter the Westgate Mall in Nairobi, Kenya, Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Armed police leave after entering the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Armed police crouch down and take position during a gun battle outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • A woman who had been hiding inside and managed to flee, sits in a state of shock, as an unidentified armed member of the security forces, above, keeps watch outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Security helps a woman outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • Civilians who had been hiding during the gun battle hold their hands in the air as a precautionary measure before being searched by armed police leading them to safety, inside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday, killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Civilians who had been hiding inside during gunbattles manage to flee from the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013. Gunmen threw grenades and opened fire Saturday killing at least 22 people in an attack targeting non-Muslims at an upscale mall in Kenya's capital that was hosting a children's day event, a Red Cross official and witnesses said. (AP Photo/Jonathan Kalan)

  • Security helps people outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • Armed special force aim their guns at the Westgate Mall in Nairobi, Kenya on Saturday, Sept. 21 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted(AP Photo/Khalil Senosi)

  • Security helps a wounded woman outside the Westgate Mall in Nairobi, Kenya Saturday, Sept. 21, 2013, after gunmen threw grenades and opened fire during an attack that left multiple dead and dozens wounded. A witness to the attacks on the upscale shopping mall says that gunmen told Muslims to stand up and leave and that non-Muslims would be targeted. (AP Photo/Khalil Senosi)

  • KENYA-UNREST-ATTACK

    A policeman carries a baby to safety after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    A Kenyan woman is helped to safety after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    A dead body lies on the ground as armed policemen try enter the Westgate mall after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    A policeman carries a baby to safety after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    A body of a man lies on the ground as armed policemen try to get entry into the Westgate after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    Injured people receive assistance from bypassers after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least thirteen on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    Injured people sit on the street waiting for assistance after masked gunmen stormed an upmarket mall and sprayed gunfire on shoppers and staff, killing at least thirteen on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)

  • KENYA-UNREST-ATTACK

    People run away from an upmarket mall after masked gunmen stormed it and sprayed gunfire on shoppers and staff, killing at least six on September 21, 2013 in Nairobi. The Gunmen have taken at least seven hostages, police and security guards told an AFP reporter at the scene. AFP PHOTO/SIMON MAINA (Photo credit should read SIMON MAINA/AFP/Getty Images)