CNN's Evan Pérez and Shimon Prokupecz
The terrorist attack on the Westgate Mall in Nairobi, Kenya, cost as little as a couple thousand dollars to pull off, according U.S. law enforcement sources.
Far from the portrayal of a sophisticated attack in the weeks after the September attacks that killed 67 and wounded 200, U.S. officials say the attack was relatively simple and cheap. Authorities believe the attackers were affiliated or inspired by Al-Shabaab, the Islamist terror group based in Somalia.
A New York Police Department report released Tuesday, produced from publicly available and investigative sources, underscored the relative ease with which the attack was carried out as well as the chaotic law enforcement response.
Four or perhaps five gunmen, who still haven't been identified, carried out the attack, law enforcement sources say. They were armed with hand grenades and AK-47-style rifles, which are cheap and readily available in East Africa. Their travel and weapons added up to under $5,000, U.S. authorities believe.
While authorities have worried for years about the vulnerability of malls and other public gathering places and have conducted drills based on such scenarios, these types of attacks are nearly impossible to prevent, officials say.
Since the 9/11 attacks, U.S. authorities have focused on stopping the funding sources for terror organizations. The Westgate attack underscores how little money it takes to carry out a deadly, high-profile attack, making the work of U.S. and other authorities that much harder.
The 9/11 attacks cost al Qaeda between $400,000 and $500,000. The 2002 Bali bombings are estimated to have cost about $50,000. The Madrid commuter train bombing in 2004 cost between $10,000 and $15,000. A year later, attackers spent about $2,000 to target the London transit system.
Ali Soufan, a former FBI agent who investigated the East Africa bombings, says a cheap attack such as Westgate is among the toughest for authorities to thwart.
"An operation like this is very easy. The cost is really, really cheap," Soufan says.
Soufan and other experts on terrorism say financial safeguards put in place in recent years are intended to stop funding to terror groups. But detecting the smaller sums that could be used for an attack are increasingly difficult. In the case of Al-Shabaab, the Somali diaspora is believed to be among the sources of funding now that the group has been dislodged from controlling territory in Somalia, where it used to collected taxes.
The NYPD sent a team to Kenya to gather intelligence and work with local investigators proving the attack. Their report says the attackers had every intention of surviving while killing as many people as possible.
The report says that despite initial information from Kenyan officials claiming 15 shooters were in the mall, it now appears that as few as four men were inside killing at random as petrified shoppers ran for their lives. Some were even hunted down after trying to hide inside storage closets.
NYPD Commissioner Ray Kelly told reporters Tuesday that "we don't know with certainty how many attackers there were. We believe there were four shooters [with the] possibility that there may have been people assisting in driving them. We don't know if any of them got away."
The report says the men used cell phones to communicate with each other after they split up to carry out the attack. A witness overheard one of the gunmen on the phone telling another to come inside the mall, according to the report. It's also believed the men used their cell phones to communicate with people possibly associated with the attack, but not inside the mall, the report says.
As the men worked their way through the mall, Kenyan police started responding to what they believed was a robbery at the mall and exchanged gunfire, wounding one of the men. That man, the report says, was seen later on camera inside a storage area looking for a way to escape.
Among the evidence investigators recovered were four cell phone SIM Cards inside a car of which the men were seen inside at the mall. Those cards were activated three days before the attack in Nairobi, according to the report.
The gunmen, whose bodies have not been found and have not been publicly identified, might still be alive, the report says. In their initial claims, Kenyan officials said that the men likely died inside the mall, but no DNA or other evidence has been found to support that, the report says.
The report was made public Tuesday to a group of business and security leaders in New York City to help illustrate the lack of communication and poor planning that went into the police response.