NAIROBI, Kenya — Forensic experts searched for clues amid the rubble at Nairobi's Westgate shopping mall Wednesday as many Kenyans demanded to know how 10 to 15 gunmen managed to hold off government security forces for more than three days.
More than 70 people, including five gunmen, were killed in the siege. The death toll was expected to rise, as forensic experts from the United States, Britain, Israel, Canada and Germany helped Kenyan police search the mall.
Kenya Red Cross officials said 71 people remained missing. Meanwhile, authorities had not confirmed how many of the gunmen were unaccounted for by late Wednesday.
Flags throughout Kenya were flying at half staff as part of three days of national mourning declared by government officials.
The U.S. ambassador to Kenya, Robert Godec, said the United States would help Kenyan investigators bring the instigators of the attack and siege to justice. The Al Qaeda-linked Somali militant group the Shabab has claimed responsibility for the assault, which was launched Saturday.
"The United States has provided technical support and equipment to assist Kenyan security forces and medical responders," Godec said in a statement. "At the request of the Kenyan government, we will provide additional assistance in the coming days to investigate this attack and to bring its organizers and perpetrators to justice. We will continue to work together with Kenya to stop the scourge of terrorism."
Kenyan Interior Minister Joseph Ole Lenku said forensic experts were carrying out DNA, fingerprint and ballistics analysis at the mall.
Engineers were also examining the structure to determine what caused three floors to collapse Monday. Some government officials blamed a fire they said was set by the militants, although Kenyan security forces set off a series of huge explosions to gain access.
The Shabab taunted Kenyans on Twitter on Wednesday, posting the Kenyan hotline numbers that families of missing people could contact. The group earlier claimed 137 bodies were buried in the rubble and that officials fired chemical agents into the mall to overwhelm the terrorists, claims the government denied.
Among the anxious families at the main morgue in Nairobi were Karen Mbithe and three other young women. They covered their noses against the stench of the dead and one of them sobbed. Mbithe was helping her weeping friend search for her missing brother, who lives near the mall.
"This is our last stop; we have checked the names all over and we've been to all the hospitals, but in vain," Mbithe said. "We are very worried and devastated."
Others used Twitter to try to trace missing people. "Has Bogonko Bosire been found?" tweeted one Kenyan, referring to a popular blogger.
Monica Nyambura told Kenyan television she was looking for her brother, Anthony Mureithi, a gas station attendant. "I checked at all the hospitals and mortuaries but I haven't found him. We are all worried."
Many Kenyans called on the government to provide answers. A list of 85 questions, headed "We the People," was circulating on the Web, demanding to know how many hostages had died in the siege, what caused the floors to collapse and whether any of the assailants had escaped disguised as hostages.
"Why won't they tell us how many hostages were rescued or where they were taken??? Why so much secrecy!" reads Question 35 on the list.
Lenku offered few answers at a news briefing. He repeated that authorities believed an "insignificant" number of civilian bodies remained under the rubble and urged Kenyans to be patient and wait for the results of the forensic investigations, which will take at least a week.
Eleven suspects were arrested at the airport during the siege, according to Kenyan security officials. In addition, officials said 10 to 15 gunmen carried out the attack and that five of them were killed, leaving as many as 10 unaccounted for. Some witnesses claimed to have seen gunmen blend into the crowd and leave the mall with fleeing civilians.
Lenku said there was no confirmation of the identities of the attackers, after reports that a British woman and two or three Americans were involved. Afetsi Awoonor, the son of Ghanaian poet Kofi Awoonor, who was killed in the attack, told the BBC that the gunmen he saw were Caucasians wearing goggles and protective vests.
Analysts believe the attack was carefully planned and that the militants smuggled heavy weapons into the mall before the assault. Some reports suggested the terrorist group had rented a shop and used it to conceal weapons, explosives and other equipment. Lenku said there was no information about that claim.
"That is a rumor we heard just like you and we will treat it as such," he said at a news briefing, before cutting short journalists' questions.
Special correspondent Soi reported from Nairobi and Times staff writer Dixon from Johannesburg, South Africa.Copyright © 2014, Los Angeles Times