Washington - The FBI and Capitol police arrested a man Friday who thought he was going to carry out a bombing attack on the U.S. Capitol but was in fact dealing with FBI undercover operatives for the past few months, federal officials told NBC News. The man, Amine el Khalifi, 29, who is from Morocco, was arrested about noon ET Friday near the Capitol after he received what he thought was a firearm and a vest containing explosives from people he thought were supporters of al-Qaida, sources told NBC News. In fact, the vest had inert material that wasn't hazardous,