A worldwide investigation has uncovered an al-Qaida loyalist's plan to blow up the PATH train tunnels under the Hudson River, thwarting a terrorist conspiracy the FBI called "the real deal," authorities said Friday. The alleged mastermind has been arrested. "The individuals were moving forward," said Special Agent Mark J. Mershon, assistant director of the FBI's New York office. They "were about to go to a phase where they would attempt to surveil targets, establish a regimen of attack and then acquire the resources necessary to effectuate the attacks." Mershon identified the plan's mastermind as Assem Hammoud, a 31-year-old Lebanese citizen...