t's hard to imagine a softer target than an enclosed, easy-to-enter space with large numbers of civilians, many of them children or elderly, milling about with no authority clearly in charge.
And the al Shabaab terrorist group that carried out this weekend's mall attack in Kenya is known to have recruited in the United States.
If you connect those dots, you get the kind of scenario that "keeps us up at night," as a federal law enforcement source told CNN's Pamela Brown: an attack at a shopping mall in the United States.
Can it happen here? Yes, say security experts, but it hasn't.
There have been shootings at U.S. malls, although not by terrorists. And there have been terror plots that were foiled.
But the U.S. has not witnessed anything close to the scope of the violent siege at Nairobi's Westgate mall.FULL STORY