Were San Bernardino terror attack warning signs overlooked?

FILE - This undated combination of file photos provided by the FBI, left, and the California Department of Motor Vehicles shows Tashfeen Malik, left, and Syed Farook. The husband and wife died in a fierce gunbattle with authorities several hours after their commando-style assault on a gathering of Farook's colleagues from San Bernardino, Calif., County's health department Wednesday, Dec. 2, 2015. (FBI, left, and California Department of Motor Vehicles via AP, File)