U.S. law enforcement sources tell ABC News the FBI is investigating new leads that involve a possible connection between people in the United States, in major east coast cities, and the London bomb plotters.
In an interview with ABC News this morning, White House Homeland Security Advisor Fran Townsend said while there is currently no indication of any plotting in the United States, she confirmed, "There are leads that the FBI is running."
With at least five, and maybe more, suspects still at large, it is the missing plotters who are the greatest security concern. Among those still at large are some of the suspected ringleaders of the London plot.
Congressman Peter King (R-NY), Chairman of the House Homeland Security Committee, told ABC News authorities are extremely concerned about the missing suspects. "They are on the loose," said King. "These are desperate, vicious people, who have a good degree of sophistication. And they're out there, if nothing else, they're available for future operations. The more deadly threat is that there is a plan B that they would be able to implement."
Intelligence officials tell ABC News the plot's trail leads directly to al Qaeda and to the Pakistani city of Karachi, where money for the plot was wired to London.
Officials say two of those arrested in London came to Karachi in the last few months for explosives training with known al Qaeda commanders.
The terrorists had planned to use a peroxide-based liquid explosive, dyed red, to appear as a sports drink. A $10 disposable flash camera was to be used as the detonating device.
Pakistani officials have made as many as nine arrests, but the suspected ringleader remains at large. Pakistani officials say this 29-year old al Qaeda commander, Matiur Rehman, was known to be planning a terror spectacular to mark the fifth anniversary of the 9/ll attacks, and some believe the London plot may have been it.
ABC News consultant Alexis Debat, a terrorism expert at the Nixon Center in Washington D.C., says, "[Rehman] is the interface between al Qaeda's leadership and thousands, if not tens of thousands, of Pakistani militants who are able to provide the muscle for al Qaeda's operations not only in Pakistan but around the world."