Twenty-four hours after a gunpowder-packed ammunition case exploded at Times Square's military recruiting booth, authorities across the U.S. and Canada are concerned about an intelligence uptick on anarchist and anti-war activities, even as they actively hunt for the bomber and any links to five suspicious individuals stopped at the Canadian border about a month ago.
ABC News has learned that Canadian authorities and the FBI met in Canada Friday to go over in detail evidence seized during that crossing and to establish what, if any, initial, firm links can be made to the New York bombing.
According to multiple senior officials from multiple agencies, a number of early versions of the crossing and the materials seized were erroneous to one degree or another, and this meeting would be the first in which all the catalogued evidence would be reviewed.
"Five or six different versions have emerged," one participant in the meeting said. "One of the purposes is to clear these up and get to the facts." A disc containing images of all the evidence seized was given to U.S. authorities at the meeting.
The pictures and other materials found in connection with the men stopped in Canada may not ultimately be directly linked to the bombing, but they represent part of what one senior official called "concentric, overlapping circles" of anti-war protest, what another called "part of a buzz on an anarchist uptick," and what still a third confirmed as a growing concern to authorities.
The lengthy letter offering political advice sent to congressmen and a picture of the Times Square recruiting center that ABC News has learned the letter writer used as a Christmas card -- while ruled out as linked to the bombing -- were also seen as an example of that uptick.
According to a senior law enforcement official involved in that part of the investigation, the letter writer was "extremely cooperative," allowed a consensual search of his home and provided information to authorities that satisfied them that he was not involved and that he may have sent at least 270 letters to members of Congress.
Officials in Los Angeles, where an anti-war protest is slated for next weekend, are paying particularly close attention to any risk of activity by a violent minority, sources said. In the past, violent anarchist activists have sought to mar peaceful anti-war protests across the country.
In New York, detectives and forensic experts working with the FBI laboratory at Quantico, Va., continued to investigate leads in Thursday's bombing based on evidence, including the explosive powder used, the military-type ammo box and the use of a bicycle -- both to compare the incident with two past New York City early morning bombings and in their effort to hunt down this bomber.
Additional searches in New York were also conducted in connection to the latest incident. The two past incidents -- at the British Consulate in 2005 and the Mexican Consulate in 2007 -- each involved a person who cased the scene, tossed homemade hand grenades at the official buildings in the early morning hours and then escaped on a bicycle, according to surveillance images and witnesses. Authorities have not ruled out or firmly linked the incidents beyond the commonalities in the method of attack and escape.
In Canada, meanwhile, as FBI agents met with that country's law enforcement and national security authorities, two individuals linked to the car stop were the subject of intense scrutiny 24 hours a day, law enforcement officials said.
That case began, ABC News has learned, about a month ago when a vehicle was stopped heading into Canada at the Phillipsburg, Quebec-Highgate Springs, Vt. border crossing. The vehicle was ruled suspicious when authorities decided there was too much luggage for the two occupants. Subsequently, Canadian authorities established that a total of five had attempted to cross the border but three of them had left the car and walked across, evading the checkpoint.
ABC News sources said of the five men, two were French, one was Italian and two were Canadian. The Canadians are known to police and are being closely watched. The other three men men appear to have left Canada.
At the time of the incident, an alert was sent to the FBI and to New York City authorities. In New York, based on the information provided by Canada, police visited the recruiting center and other businesses in the Times Square area to determine if there had been any suspicious activity noticed. At the time, there did not appear to be any. The suggestion that specific images of the recruiting center were part of the original alert were discounted by officials.
When contacted, Canadian authorities would neither confirm nor deny any portions of the investigation.