CHICAGO — Prosecutors haven't denied that an expanded U.S. phone and internet surveillance program triggered an investigation that led to terrorism charges against a Chicago-area teenager, a defense attorney said Thursday.

Thomas Durkin told a federal judge that he needs to know how the government compiled evidence against Adel Daoud, resulting in charges that he tried to set off what he thought was a car bomb next to a Chicago bar.

In a late Wednesday filing in U.S. District Court in Chicago, prosecutors indicated that the evidence against the 19-year-old U.S. citizen was gathered using traditional methods, though they offered no details.

A spokesman for the U.S. Attorney's Office in Chicago, Randall Samborn, declined to comment on the filing.

The vastly expanded surveillance program, revealed in a leak by a former CIA employee last week, has stirred debate over personal privacy rights versus national security needs.

But Durkin said the language of the filing suggests that the expanded spying program may have triggered an initial investigation into Daoud. He said he would continue to press for more clarity from the government.

"We're not done on this," he said Thursday, adding that the judge overseeing the case would have to rule at some point on the defense request for more detail.

Durkin has said authorities may have singled out Daoud only after surveillance data indicated he viewed the online Inspire magazine, produced by al-Qaida affiliates. Daoud has claimed he viewed the material as part of work on a high-school term paper.

If he learns the surveillance program kick-started an investigation, Durkin has said he could ask a higher court — possibly the U.S. Supreme Court — to have the case thrown out on constitutional grounds.

"Anyone who is concerned with civil liberties in this country should want the Supreme Court to visit (the expanded surveillance program) and rule on its the constitutionality," he said earlier this week.

Daoud, of Hillside, was arrested last year in what authorities described as an FBI sting, during which they said the public was never in danger. Daoud has pleaded not guilty and remains jailed in Chicago as he awaits trial, which is set to begin Feb. 3.