Read the complete story here. But the bottom line is:
A new book written by a former FBI consultant claims that al-Qaida not only has obtained nuclear devices, but also likely has them in the U.S. and will detonate them in the near future.
Williams claims that al-Qaida has been planning a spectacular nuclear attack using six or seven suitcase nuclear bombs that would be detonated simulantaneously in U.S. cities.
Ground zero would likely be Washington D.C. and the major population centers.