Federal authorities are closing in on the man they say is a person of interest in the Times Square car bomb attempt this weekend, who is described as a naturalized American citizen who hails from Pakistan and just returned after spending five months there.

There is growing evidence the bomber did not act alone and had ties to radical elements overseas, with one senior official telling ABC News there are several individuals believed to be connected with the bombing and that at least one of them is a Pakistani-American.

Attorney General Eric Holder said today the investigators had made "substantial progress" in tracking the man who drove a Nissan Pathfinder into New York's Times Square with a crude bomb that failed to detonate.

Officials declined to provide the specifics that led them to believe there were overseas links to a larger plot.

Authorities said another clue in the investigation is a video posted online early Sunday morning by persons in Connecticut, who may have been involved in the bomb attempt and are being sought by law enforcement. The video, posted on a site registered one day before the attack, has the Taliban in Pakistan claiming responsibility for the attempted bombing.

The Washington Post, quoting Obama Administration sources, said the attempted bombing "increasingly appears to have been coordinated by several people in a plot with international links."

Other law enforcement officials said the investigation was closing in on the driver of the vehicle and an unknown number of others connected to him.

"This is moving very fast because they left behind a treasure trove of evidence in the unexploded car," one US official told ABC News.

Officials told ABC News Senior Justice correspondent Pierre Thomas that the Connecticut owner of the vehicle told them he had sold the Nissan SUV last month in an unrecorded sale to an "Arabic or Latino looking man" in his 20's or 30's, for a few hundred dollars in cash.

The license plate on the car was apparently stolen from an auto repair shop outside Bridgeport, Connecticut, according to law enforcement officials.

The authorities told ABC News that the previous owner provided a description of the man who bought the car, and told investigators the vehicle was sold for several hundred dollars in cash, with no written records identifying the purchaser.

The license plate found on the Pathfinder also came from Connecticut, #98CY09, according to photographs of the vehicle.