WASHINGTON — The Pakistani-American accused of a failed car bombing in Times Square is believed to have worked alone in the United States on the plot almost immediately after returning from a five-month visit to his native land, authorities said Wednesday.
They said they have yet to find a wider link to extremist groups.
Faisal Shahzad was cooperating with authorities for a third day, sending investigators scrambling to run down possible leads and again delaying his initial court appearance.
Two videos surfaced in the case, one allegedly showing Shahzad walking away from the scene in Times Square on Saturday and the other allegedly showing him buying fireworks in Pennsylvania that may have been used in constructing the bomb.
Shahzad faces terrorism and weapons charges after authorities said he admitted rigging a Nissan Pathfinder with a crude bomb of firecrackers, propane and alarm clocks based on explosives training he claimed to have received in Pakistan.
Source: No other U.S. suspects
That claim has stoked fears that he was part of an international plot. But a law enforcement official told the AP that authorities don't believe there any other U.S. suspects and that several arrests in Pakistan in the past two days were not related.
If Shahzad was part of a larger organization, it would serve as a reminder that nearly a decade after the Sept. 11, 2001, attacks, foreign terrorists are still trying to strike on U.S. soil. Like the unsuccessful Christmas Day airline bombing near Detroit, the Times Square plot could be flaunted by terrorists, even in failure.
And if an attacker operated alone, the plot would raise questions about how investigators can prevent an assault when there are few warning signs, the prime suspect has no known ties to terrorists and the methods are crude.
Law enforcement officials, speaking on condition of anonymity to discuss the case, said Wednesday they had not verified the statements they said Shahzad had made that he was trained in Pakistan for the attack. The Waziristan region is home to several terrorist and militant operations.
But one senior counterterrorism official told NBC News on Wednesday that Shahzad's interrogation pointed toward a role by the Taliban in training and to only a slightly less degree to directing him.
Sharing information pays off
The FBI was able to identify Shahzad's name because of information Customs and Border Protection officials shared months earlier, according to a law enforcement official who spoke on condition of anonymity to discuss the investigation.
When Shahzad returned from Pakistan in February, he went through extra screening at U.S. Customs because of rules put in place after the attempted terrorist attack on Christmas Day. Customs officials noticed Shahzad had traveled to Pakistan previously, but for weeks, instead of months like his most recent trip. Shahzad came back to the U.S. without his family and without a return plane ticket.
When Customs officials come across people with suspicious travel patterns such as these, they send information along to the FBI.
Video: Bomb attempt prompts new no-fly rules As the FBI was following leads from the SUV left in Times Square, they found a phone number in the records of a throwaway cell phone that Shahzad had used when he was buying the SUV in Connecticut. The number matched a phone number Shahzad gave to Customs officials when he returned from his last trip. The FBI then contacted Customs about the match, and Customs provided other travel information on the suspect.
Police recovered the video showing Shahzad in a white baseball cap and dark jacket walking along Shubert Alley moments after witnesses saw the Nissan Pathfinder ditched Saturday in a no-standing zone across from a Broadway theater, a law enforcement official told the AP, speaking on condition of anonymity because of the ongoing investigation. Authorities were weighing whether to release the video.
Shubert Alley is the same spot seen in another video that was released by police on Sunday that shows a second man shedding his shirt near the SUV. The unidentified man was never referred to as a suspect but police had said they sought to interview him. Investigators don't believe he was involved in the attack, an official familiar with the probe told the AP.
The official said the video had the unintended effect of falsely reassuring Shahzad that he wasn't a target.
Shahzad, who was charged Tuesday in the plot, was hauled off a Dubai-bound plane he had boarded Monday night at Kennedy Airport despite being under surveillance and placed on the federal no-fly list.
The government said Wednesday it would require airlines to check no-fly lists within two hours of being notified of updates. The airline apparently failed to check the latest version of the terror watch list that included Shahzad's name. Until now, airlines had been required to check for list updates every 24 hours.
Shahzad had previously lived in Shelton but got a low-rent apartment in nearby Bridgeport when he returned from Pakistan. Landlord Stanislaw Chomiak said Shahzad lived alone and he never saw him with anyone.
Chomiak said that on Saturday night — after the failed bombing — Chomiak said Shahzad called him and asked to be let into his building, saying he had lost his key.
"He said he was hanging out with a friend in New York and he must have lost the key somewhere," Chomiak said.
Authorities said he had actually left his keys hanging in the rear hatch of the SUV. Law enforcement sources told NBC News that Shahzad drove another car to Times Square the day before the attempted bombing, apparently to be his getaway car.
But after he left his keys in the SUV, he had to take the train home instead.
Buying a gun
Interviews Wednesday with business owners shed light on a series of purchases Shahzad made of a gun and fireworks near his Bridgeport, Conn., home and in Pennsylvania that authorities say proved a rapidly accelerating plot.
Shahzad is on video buying six to eight boxes each containing 36 Silver Salute M88 fireworks — a consumer-grade product mostly made up of paper — from Phantom Fireworks in Matamoras, Pa., on March 8, said store vice president William Wiemer.
Even if used together, the fireworks couldn't have caused a large explosion, Wiemer said.
"The M88 he used wouldn't damage a watermelon. Thank goodness he used that," said Bruce Zoldan, the company's president.
Video: TSA implements new no-fly requirements Two people familiar with the investigation, speaking on condition of anonymity because of the sensitivity of the case, said Shahzad slipped past federal surveillance Monday afternoon and drove to the airport, where his car was found with a gun inside. He had been spooked by news reports that police were seeking a Pakistani suspect in Connecticut.
Police in Shelton, Conn., said Shahzad legally bought a Kel-Tech rifle from a dealer after passing a criminal background check and a 14-day waiting period. The owner of the gun shop declined comment.
‘We are a target’
Sen. Frank Lautenberg, D-N.J., and Rep. Peter King, R-N.Y., have introduced legislation that would give the attorney general authority to deny guns and explosives to known and suspected terrorists.
A gun owner who objected to an attorney general's finding could challenge the ruling.
Kelly and New York Mayor Michael Bloomberg testified Wednesday in favor of the legislation.
Asked about lessons learned from the failed bombing attempt, Bloomberg said that preparation for such an incident paid off: Street vendors were vigilant and responders reacted according to their training.
And he warned that more attacks will certainly occur in New York.
"We are a target. We are going to be a target again," he said.
NBC News’ Robert Windrem and Pete Williams, WNBC’s Jonathan Dienst, The Associated Press, and Reuters contributed to this report.