The Islamic State of Iraq and Syria (ISIS) may be dominating the headlines and stealing attention with its prolific propaganda, but CBS News' Bob Orr reports, another group in Syria -- one few have even heard of because information about it has been kept secret -- is considered a more urgent concern. Sources tell CBS News that operatives and explosives experts from Osama bin Laden's old al Qaeda network may again present an immediate threat to the U.S. homeland. At two dozen foreign airports, U.S.-bound passengers are undergoing enhanced security screening. Agents are searching for hidden explosives. Laptops and phones...
