NEW YORK – The Times Square bomb suspect claimed during his lengthy interrogation that he received financial support from the Pakistani Taliban for his failed one-man operation, two U.S. law enforcement officials close to the probe said Friday.

Investigators believe funding for Faisal Shahzad in the United States was channeled through an underground money transfer network known as “hawala,” the officials said. But, one official said, “there’s a belief that no one in the U.S. who got him the funds was aware of what they were for.”

The Pakistani-American was the only person in the United States who was “operational” in the plot to attack Times Square with a crude gasoline-and-propane car bomb on May 1, the official said. The bomb did not explode and no one was hurt.

The attempted attack set off a massive probe involving hundreds of federal agents in several cities. Nearly three weeks later, investigators have so far concluded that once he was funded, Shahzad acted alone, the officials said.

A South Portland, Maine, man and two Massachusetts men were arrested last week on immigration charges as authorities followed the money trail. U.S. Department of Justice officials have said they were suspected of providing money for Shahzad, but the officials say the three may not have known they were supplying funds that supported terrorism.

The investigation’s main asset has been Shahzad. After he waived his right to an initial court appearance and agreed to cooperate after his May 3 arrest, a special interrogation team of FBI, CIA and Defense Department investigators was brought in to grill him in a Brooklyn hotel room, an official said.

The team was there to “build his trust,” the official said. “But he was never really worried about talking. It was clear from the start, he wanted to.”

Shahzad told investigators he was “supported” by the Pakistani Taliban, which initially claimed responsibility for the bombing in three separate videos, then later denied any role.

U.S. Attorney General Eric Holder said earlier this month of the Taliban: “We know that they helped facilitate it; we know that they helped direct it. And I suspect that we are going to come up with evidence which shows that they helped to finance it.”

Authorities say that in the weeks before he drove a car bomb into Times Square, Shahzad plunked down $1,300 in hundred-dollar bills for the SUV and bought a gun for about $400. They say he later paid cash for a plane ticket the day he tried to flee the country.

For Shahzad, the underground series of cash transfers in the United States “was like his Western Union,” an official said.

An official called the funding for Shahzad’s plot “very haphazard,” with some money being transferred and some delivered. Officials have been investigating financing by the Taliban and in Pakistan.