Police and federal agents ran down stolen vehicles, stopped suspicious trucks, issued "Be On The Look Out's" (BOLOs) for persons suspected of harboring animosity that could be directed at Ground Zero or the President as well as continuing the hunt for terror plotters.
The BOLOs were sent for subjects including a 2003 Afghanistan veteran believed armed with handgun and believed to have crossed the George Washington Bridge Saturday morning heading from New Jersey to New York.
That man, missing since Tuesday from his job, had been located in New Jersey by authorities a day earlier, and was the subject of a Joint Terror Task Force BOLO when his EZPass alerted police he had crossed the bridge.
Authorities have also investigated a stolen van on Long Island, a missing rental van near New York, possible stolen vans in Maryland, wiring boxes on bridges, packages and bags left in boroughs outside of Manhattan, airport security breaches at JFK and suspicious packages at Dulles -- all seen since Friday night and all given extra scrutiny.
In the midst of the scramble Saturday, a DHS analyst sent out a bulletin that multiple sources in law enforcement say erroneously linked a man to the alleged anniversary plot. That document was rapidly pulled back, but the JTTF in North Carolina continued to be besieged by calls.
"We found out it came from an overzealous DHS analyst. Charlotte does have a case on him but he is not one of the three. DHS is going to get spanked. Charlotte is getting inundated with calls," one official told ABC News around 1 a.m.
For residents of New York, solemnity is mixed with security today as traffic stops continue a half-mile from ground zero. Pedestrians, too, are not immune from random stops by police.
Where the towers once stood, battalions of police officers have fanned out to protect the thousands attending the 9/11 anniversary ceremony.