Napolitano Farewell: 'No 100% Guarantees In This Business'

CBS NEWS: Outgoing Homeland Security Secretary Janet Napolitano said homegrown radicals like the Boston Marathon bombers may be just as much of a threat to the U.S. as international jihadists.

In farewell speech, Napolitano praises homeland security responseNapolitano resignation deals new blow to DHS leadershipWhen asked if Boston is a reminder that there’s no way to prevent every terrorist act, Napolitano said, “what we can do is be always thinking about threats we could confront,” but, she added, “there are no 100 percent guarantees in this business.”

Napolitano added that the greatest transnational threat likely comes from al Qaeda in the Arabian Peninsula, a Yemen-based group which has repeatedly tried to target the U.S. with bombs aboard aircraft. And with the U.S. military poised to strike Syria, the Department of Homeland Security is also warning of possible retaliatory strikes including cyber attacks.

While Napolitano is leaving the top Homeland Security job Friday to run the University of California, President Obama has yet to name a successor.