New York (CNN) -- A naturalized American citizen from Pakistan arrested overnight in the Times Square bombing investigation will appear Tuesday morning in a Manhattan federal courtroom to face formal charges in the case.

Faisal Shahzad, 30, was on board an Emirates Airlines plane at New York's John F. Kennedy International Airport when he was taken into custody, law enforcement officials said. The flight was headed to Dubai, where Shahzad was going to connect to Islamabad, Pakistan, a senior airline official said Tuesday.

Shahzad was arrested at 11:45 p.m. ET Monday, Attorney General Eric Holder said early Tuesday from Washington.

A federal law enforcement source said Shahzad nearly made it out of the country.

"They just caught him at the last second," according to the source, who said Shahzad was on board the flight to Dubai and the jetway had been pulled back when the plane was called to return to the gate.

Investigators were searching a house in Bridgeport, Connecticut, early Tuesday in connection with the failed bomb attack.

Speaking to reporters, Kim Mertz, FBI special agent in charge, would not disclose any details of the search.

"Our first mission was to ensure the safety of the public and our law enforcement officials," she said. "That is complete and the public is safe."

Along with several patrol cars, a Connecticut State Police bomb squad truck was called to the two-story building at Sheridan Street and Boston Avenue.

Shahzad is believed to be the person who drove the sport utility vehicle used in the attempted bombing to Times Square, a law enforcement official said.

The Nissan Pathfinder had its vehicle identification number removed from the dashboard. Police climbed under the SUV and retrieved the VIN from the bottom of its engine block. This, said the official, led investigators to the registered owner of the vehicle and then to Shahzad, who had purchased the SUV.

Shahzad claimed to have acted alone in the attempted bombing, said another law enforcement source with knowledge of the investigation. The Joint Terrorism Task Force investigating the bombing attempt has said it's considering the possibility that the attempt involved more than just a "lone wolf."

Law enforcement officials had said that Shahzad was the person who bought the Nissan Pathfinder used in the bombing attempt, but had not placed him behind the wheel.

Shahzad was one of three passengers taken off Emirates Flight 202 late Monday, the senior airline official said.

A federal law enforcement source said Shahzad has traveled to Dubai before, most recently in June 2009. He returned to the United States in early February.

Investigators believe the plan was an intended terrorist attack to set off explosives Saturday night in the heart of Midtown Manhattan, but the individuals didn't have the expertise to detonate their device, according to a source familiar with the investigation.

The Nissan Pathfinder had been sold three weeks ago in a cash deal with no paperwork exchanged, a law enforcement source with knowledge of the probe said Monday. The $1,800 deal was closed at a Connecticut shopping mall, where the buyer handed over the money and drove off, the source said.

A federal law enforcement official said the information gained from the vehicle's sale was the linchpin in the case.

New York Mayor Michael Bloomberg praised federal and local law enforcement agencies, saying their focused and swift efforts led to an arrest after only 48 hours of around-the-clock investigation.

"I hope their impressive work serves as a lesson to anyone who would do us harm," Bloomberg said.

Shahzad became a U.S. citizen on April 17, 2009, which aided investigators in the case, a federal law enforcement source said. Because of his recent change in status, authorities had his picture and were able to show it to the seller of the vehicle, who identified Shahzad as the purchaser.

A bomb made up of propane tanks, fertilizer and gasoline failed to detonate inside the SUV. New York Police Commissioner Ray Kelly said the device could have produced "a significant fireball" had it detonated properly.

Earlier, authorities said they were searching for two people they wanted to question in connection with the would-be bombing. A video obtained from a tourist in the area shows a person apparently running north on Broadway, while another video features a balding man with dark hair removing a shirt and putting it in a bag before walking out of view of the camera, which was inside a restaurant.

"These are not suspects," Kelly said. "These are people we would like to speak to."

Suspect's Pakistan residency

Shahzad has a Karachi identification card, a document that shows Pakistani residency, and the suspect's family is from northwestern Pakistan, Pakistani Interior Minister Rehman Malik said.

The U.S. ambassador to Pakistan notified Malik about Shahzad's arrest on Tuesday morning, and the Pakistani official said his government will work with the U.S. in the investigation.

"We will fully cooperate and help the government of the United States of America to identify and bring this suspect and his associates to justice," Malik said.

The question of who was behind the failed bomb attempt was the subject of intense scrutiny Monday. Kelly said it was "too early to say" whether the attempt was carried out by a one person, international terrorists or any other type of network.

Pakistani Taliban leader Hakimullah Mehsud appeared on a video released less than 24 hours after the attempt, claiming Taliban fighters were prepared to inflict "extremely painful blows" in major U.S. cities. But a senior U.S. military official said there was no "credible evidence" at the early stages of the investigation that the Pakistani Taliban was responsible for the Times Square bomb incident.

And one counterintelligence official told CNN there was no evidence of any communications among terrorist organizations overseas about the device after Saturday night's attempt.

"People overseas were not giving high-fives ... or saying anything about the bomb not working," the official said. "There is no indication that there was that kind of tie."

Another U.S. official said the Pakistani group has never shown "trans-national capabilities" such as al Qaeda. But such a possibility is "not something one can rule out at this early stage," said the official, who spoke on condition of anonymity because of the sensitivity of the information.

But Pakistan's Taliban movement has been linked to a 2008 plot to blow up subway stations in Barcelona, Spain, and at least two of the 11 men convicted in the plot came to Barcelona from Pakistan, Spanish prosecutors said.

Jim Cavanaugh, a former agent with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, said the bomber could have been "internationally inspired," but the device showed little sign that a group such as al Qaeda was behind it.

"Their bombs would be better funded, better fused, better materials, better knowledge," he said.

The device inside the Pathfinder was made up of propane tanks, gasoline and fertilizer that turned out to be of a nonexplosive grade, along with a metal pot containing wiring and firecrackers. More firecrackers were found in a can on the back seat of the vehicle, sandwiched between two full, 5-gallon gasoline cans and connected by wires to clocks.

Cavanaugh called the bomb "a Rube Goldberg contraption" that would have been difficult to set off.

"That does not mean that the bomb's not deadly," he said. Someone close by could be hurt or killed. "But it's not a very reliable working system, a fusing and firing system, at all," he said.

Kevin Barry, a former New York bomb squad member, said the device had "no known signature," a style of construction that might link it to known terrorist groups. That suggests it was the work of either an individual or a new organization, said Barry, an adviser to the International Association of Bomb Technicians and Investigators.

Barry said the detonating mechanism lacked the energy needed to set off the explosion properly.

New York police have been examining the device for clues such as fingerprints, hair and fibers since Saturday. The vehicle and bomb components were taken to the FBI's forensic laboratory in Quantico, Virginia, on Monday, FBI spokesman Richard Kolko said Monday evening.