United States FBI and CIA agents continue to assist in the investigation of last Saturday's deadly terrorist attack on an upscale shopping mall in Nairobi, Kenya that killed at least 72, and wounded nearly 200 more innocent victims.
Last Saturday's terrorist attack on the Westgate shopping mall was the largest in Kenya since the 1998 bombing of the U.S. Embassy.
Since Wednesday, FBI agents have been collecting fingerprint, DNA and ballistics to determine the identities and nationalities of both the victims and al-Shabab gunmen.
In addition to the official number of casualties, the Red Cross has received dozens of missing persons reports by family members.
A U.S. counter-terrorism official said over the last year, "soft targets" in Nairobi have been under surveillance, including the Westgate Shopping Mall, and the Nakumatt supermarket, and several hotels and restaurants popular with westerners.
The well organized terrorist attack appears to have been part of a broader series of operations in Kenya and the region by Al-Shabab or other Al Qaeda-linked forces internationally.
Kenyan officials said on Friday that al-Shabab leased a store inside the Westgate shopping mall for a year prior to Saturday's attack. Authorities say the store was used to smuggle heavy machine guns and explosives into the mall weeks prior to the attack.
At a press briefing on Friday, Kenya's Interior Minister Joseph Ole Lenku confirmed that police are holding eight suspected members of al-Shabab in connection with Saturday's terror attack, and that 3 additional suspects were interrogated and released.
A Kenyan official and several eyewitnesses at the scene of Saturday's deadly attack said a woman was among the terrorists who ambushed the shopping mall.
At the request of Kenyan officials, Interpol Police in Britain issued a global warrant for the world's most wanted woman, Samantha Lewthwaite on Thursday.
U.S., British and Kenyan officials say there is no evidence to suggest that Lewthwaite, a 29-year old mother and Muslim convert from Britain dubbed the "white widow" was part of Saturday's mall attack.
Kenyan police say there is evidence linking Lewthwaite to al-Shabab, however, the warrant is for terrorism related charges stemming from an incident in 2011.
The United States Department of Homeland Security has warned over the last few year about an increase of American citizens joining terrorist organizations. The FBI said more American citizens were recruited by al-Shabab than any other terrorist group.
The largest population of al-Shabab in the U.S. live in the Somalian community in Minneapolis, Minnesota.
Al-Shabab's Twitter feed on Sunday, the group identified 3 of the terrorists involved in the Westgate Mall ambush as Americans from Minnesota and Missouri.