Faisal Shahzad bought fireworks in Pa.

He came, he shopped, he left within an hour.

That was two months ago.

But on Tuesday - after a two-day search of surveillance footage - video of alleged terror suspect Faisal Shahzad's March 8 visit to a northeast Pennsylvania fireworks store was turned over to federal authorities.

The video reportedly shows Shahzad purchasing at least some of the 152 M-88 firecrackers recovered from his explosives-rigged SUV last weekend in New York's Times Square.

"We feel that the information we have provided will help lead to a slam-dunk conviction," Bruce J. Zoldan, owner of Ohio-based Phantom Fireworks, said Wednesday in a telephone interview.

Phantom's store in Matamoras, along the upper Delaware River town where Pennsylvania, New Jersey, and New York converge, is where Shahzad allegedly went in search of fireworks that Monday in March.

The Matamoras location, along I-84, is the closest legal fireworks store to New York City, Zoldan said.

"He came in at approximately 12:30 and spent about 45 minutes shopping around," Zoldan said. "He seemed very calm. One of our sales clerks helped him select some items and the cashier checked him out. He was on his way."

For a would-be terrorist, though, it was a fool's errand, Zoldan said.

The M-88s, being consumer-grade fireworks the size of a thumb, pack only a fraction of the explosive power of the similar sized M-80s, which cannot be purchased legally by the public, he said. M-88s, he added, must be lit individually or they will not explode; lighting one will not make a string of others go off - as Shahzad presumably had intended in order to detonate containers of gasoline in the vehicle.

"Had he been able to purchase M-80s illegally, the outcome in Times Square would have been catastrophic," Zoldan said. "Those are 1,000 times more powerful than what he bought in our store, and a bag of M-80s would mass-explode."

Zoldan, of Youngstown, Ohio, first heard of the botched bombing Saturday night while driving home from the Kentucky Derby.

"My gut told me that he could have been using our products, because of the stores we have on the Pennsylvania border," he said.

The next day, when Zoldan heard that the fireworks in the Times Square SUV were a brand sold by Phantom, he contacted the company's security chief, a former FBI agent, who in turn notified federal investigators.

As authorities focused on Shahzad as a suspect, they searched for his name in Phantom's mandatory customer-registration database. It appeared that he had inverted his name when signing the form, listing himself March 8 as Shahzad Faisal.

A search began for footage of his visit that day.

Luckily for investigators, spring is a slow season for fireworks stores.

Phantom's surveillance cameras are motion-activated, Zoldan said, and delete old footage as they fill up. The relative lack of business enabled the searchers to have video spanning 75 days still on hand.

"That is unusual," he said. "If we had been into our busy season of May and June, that wouldn't have happened."

On Tuesday, a "very clear video" of Shahzad was located, Zoldan said. FBI officials have asked Phantom not to make it public.

With records of Shahzad's purchase now in federal hands, Zoldan said he was not sure how many M-88s Shahzad bought. They are sold in boxes of 36 or 72, "and our stores are always buy one, get one free," he said. "If he bought a 72 box, he would have had at least 144."

A federal criminal complaint says that 152 of the firecrackers were found in Shahzad's Nissan Pathfinder, along with alarm clocks connected to wires, containers of gasoline and propane, and bags of fertilizer.

Court records in New York also show that Shahzad had used a prepaid cell phone to call a Pennsylvania fireworks store April 25.

Zoldan said he did not know whether that call had gone to one of his stores.

"We are sad," he said, "that a product made to celebrate America's birthday was used to try to create the opposite effect."