Shahzad, who admitted driving an explosives-laden SUV into the heart of New York City's Time Square Saturday, was a naturalized U.S. citizen previously unknown to law enforcement. His plot may represent a new breed of terrorist threat.
"He may be … what we're starting to see more and more, the unguided missiles. By that I mean, they're given some training in terrorism, and then they're just told to go do something, without control, without anything else. And that's kind of frightening," Skip Brandon, former assistant director of the FBI, told CBS' "The Early Show".
Shahzad, 30, told investigators he received explosives training in his native Pakistan, but claimed to have been acting alone, reports CBS News national security correspondent Bob Orr. He was originally scheduled to be arraigned Wednesday on terrorism and weapons of mass destruction charges, but his court appearance has been delayed.
His plot is the latest in a string of small-scale of attacks. In November, Army psychiatrist Maj. Nidal Malik Hasan, who had links to a radical Muslim cleric in Yemen, killed 13 people in a shooting rampage at Fort Hood. On Christmas day, Umar Farouk Abdulmutallab tried to detonate explosives on board a Detroit-bound plane.
"For a long time we thought that al Qaeda … wanted to do another attack against the United States, but they wanted to make it as big, if not bigger than 9/11," Rep. Peter Hoekstra, R-Mich., told "The Early Show". "That's very, very hard to accomplish. Now you're seeing splinter groups still affiliated with al Qaeda, but they have independent leadership, independent strategy, and it appears that they are more than willing to accept smaller attacks."
While Shahzad showed no evidence of terrorist tendencies in the United States, Hoekstra questioned whether his activities in Pakistan should have raised red flags.
"Did he leave some footprints in Pakistan that we should have picked up as he was interacting with the Taliban and probably other terrorist groups," he asked.
Hoekstra also questioned whether the United States was using all the tools at its disposal to guard against these unassuming attackers.
"I think that there are certain tools that we should have available that we're not using right now. And I think this administration is going to come under increasing pressure to explain why some of these tools are not available right now, and why they're not being used."
Also troubling is the fact that Shahzad nearly eluded capture, even after law enforcement identified him as a suspect. He slipped away undetected from his Bridgeport, Conn., home, even though he was under surveillance by the NYPD and federal authorities.
On top of that, Shahzad managed to board a Dubai-bound plane, even after he had been added to the federal no-fly list. He was arrested after authorities called the plane, which had been taxiing to the runway, back to the terminal.
"Well, this is the question of the day. How could this happen?" Brandon said. "This is not necessarily rocket science, and we've had a long time to work out all the glitches. It shouldn't have happened. But, in the end, we also have to remember, that, in fact, it did work. Very close call on it, but it did work."
Brandon said the system " has to be reviewed, and fine tuned."
"Unfortunately we've been through this for a number of years and had a number of incidents. It has to be fixed right now."