The NYPD and FBI are investigating the improvised explosive device recovered from outside Gracie Mansion during Saturday's protests as a potential act of terrorism in part because one of the two suspects in custody directly reference ISIS in statements to law enforcement, multiple people familiar with the matter said. The device was one of two ignited during dueling protests outside of the official residence of Mayor Zohran Mamdani on Manhattan's Upper East Side. The law enforcement investigation continued into Sunday afternoon, when the NYPD Bomb Squad dispatched a robot several blocks away from the protest scene to search a car...