Nairobi — In August 2012, African authorities arrested Mahdi Hashi, Ali Yassin Ahmed and Mohamed Yusuf, all in their twenties, as they were on their way to Yemen.
Months later the three defendants were presented to a U.S. district court in Brooklyn, New York, to answer charges that they joined and trained with Somalia-based al-Shabab militants.
The U.S. media outlet CBS News reports a court document related to the case indicates the men have substantial knowledge about al-Shabab plans to develop a chemical weapon for attacks western interests in the region against.
While recent four-day assault on Nairobi's Westgate mall shows the organization can commit major acts of terrorism across international borders, whether it is capable of handling chemical weapons technology is another question.
After steadily losing ground in Somalia, weakened by a concerted military effort by a multinational African Union force and Somali government troops, al-Shabab once controlled large portions of the country. More recently they have only been able to carry out hit-and-run attacks.
According to Abdullahi Halakhe, a Horn of Africa researcher who formerly worked for the International Crisis Group, the group's losses make it difficult for them to obtain and use chemical weapons.
"There are so many chemical engineers in the organization, but some of them have been killed," he said. "[A] high level of [personnel] and resources have been tracked down and killed, so it will be very hard."
Although migration of foreign terrorists into Somalia could alleviate that problem, Halakhe says, the rebel group would still face the challenge of storing and handling the chemicals.
"The possibility is very much there, because the movements of people - ex-Soviet [fighters or Jihadists], and the Afghanistan and Pakistan movement is there [in Africa], and Somalia was their target in the Horn," he said. "The capacity could be there but the facilities would be really a big struggle for them to pull it off."
Despite the odds, however, Halakhe says one cannot dismiss the possibility that al-Shabab could one day possess a chemical weapon.
And even without chemical arms, says Anneli Botha, senior terrorism researcher with the Institute for Security Studies, nothing can stop any terror group from trying to get chemical weapons, and that al-Shabab, in the meantime, will use any material at their disposal.
"If they want, they will try to find a way," she said. "But by the same token, with what they have - AK-47s, hand grenades, and they also know how to build IED's - they tend to go to their roots in some of this cases."
The Kenyan government has said the Nairobi mall attack was carried out by a group of multinational attackers with surprising sophistication.
Halakhe said if the allegations about al-Shabab seeking chemical weapons are confirmed, it suggests east Africa is facing a new type of danger from terrorism.