A man accused of developing chemical weapons for the extremist al-Shabab group that was behind the Kenyan shopping centre atrocity is a former British citizen, it has been reported.
Madhi Hashi, formerly of Camden, north London, is suspected of being a leading figure in the al Qaida-linked group which has claimed the assault at the Westgate mall in Nairobi that killed at least 67 people.
The 24-year-old is accused of being a member of "an elite al-Shabab suicide bombing unit" and having "specific knowledge regarding significant al Qaida members operating in East Africa who sought to carry out attacks against US and Western interests", The Times reported.
The newspaper said that while not charged with offences relating to chemical weapons, it is alleged that Hashi and his two co-accused had "substantial knowledge" on an al-Shabab department that was developing chemical weapons and that this will form part of the case against them.
Hashi and the two other men are awaiting trial in New York. It is alleged that between 2008 and 2012, they travelled to Somalia to receive weapons and explosives training from al-Shabab and were ''deployed in combat operations'' there.
The trio were captured while preparing to travel to Yemen to allegedly meet up with al-Shabab members.
A Foreign Office spokesman said: "The FCO became aware of Hashi's detention by US authorities on terrorism-related charges in 2012."
It is understood that Somalian-born Hashi came to Britain in 1995 and became a citizen in 2004, but that last year his family was told Home Secretary Theresa May had revoked his citizenship.