NEW YORK (AP) -- A TV news producer accused of blackmailing David Letterman in exchange for keeping quiet about his sexual affairs was only trying to sell the late-night comic a screenplay, a defense lawyer said Tuesday.

Robert J. "Joe" Halderman's lawyer asked a judge to toss the attempted first-degree grand larceny case, saying the producer did nothing illegal in slipping Letterman documents alluding to the "Late Show" host's dalliances and taking a $2 million check from Letterman's lawyer.

"There was no extortion. There was a screenplay for sale," the lawyer, Gerald Shargel, said outside court. "There was a commercial transaction. Nothing more."

But a lawyer for Letterman said the exchange was a shakedown, not a sale.

"It's classic blackmail, no matter how Mr. Halderman's lawyer wants to dress it up," Daniel J. Horwitz said outside court.

In papers filed Tuesday, Shargel argued that the indictment against Halderman should be dismissed because his conduct wasn't a crime, among other claims. Assistant District Attorney Judy Salwen said she was confident a judge would find the indictment was on solid legal ground.

State Supreme Court Justice Charles Solomon is expected to rule in January. Horwitz said Letterman is prepared to testify if the case goes to trial.

Halderman acknowledges getting a package into Letterman's car on Sept. 9 that included the supposed screenplay "treatment" -- or synopsis -- and some "source material."

Authorities say the materials included a letter saying Halderman needed to make "a large chunk of money" and a claim that the screenplay would depict how Letterman's world would "collapse around him" when information about his private life was disclosed. Photos, personal correspondence and portions of a diary also were enclosed, authorities said.

The diary entries were allegedly written by Halderman's former girlfriend and outlined her affair with Letterman.

Authorities then taped two conversations between Letterman's lawyer and Halderman -- including an exchange in which the lawyer gave Halderman a phony $2 million check after he demanded it as hush money, the Manhattan district attorney's office said. Halderman was arrested after depositing it.

The day before prosecutors unveiled the case last month, Letterman divulged it on his show, acknowledging he had had sex with women who worked for him.

Shargel's court filing said Halderman simply realized he had "a valuable subject for a book or a movie" and sold it to Letterman, threatening to do nothing more than sell it elsewhere if the TV host rejected it.

"I have no plans to do anything other than either sell you this option -- this screenplay -- to you and therefore you own the story. Or if you don't and you're not interested, as I've said, then that's fine, and I will proceed, and I will do what I want to do, which is what I've been thinking about doing, anyway -- which is writing a book," Halderman told Letterman's lawyer in one of the taped exchanges, according to the filing.

Letterman's lawyer said criminal charges would follow if Halderman released the information himself, the filing said. Halderman, it said, responded: "I don't agree with your position on that."

The filing says Halderman had evidence that "Letterman had created and fostered an environment of workplace sexual misconduct" that amounted to sexual harassment -- a question that has become an issue since the comic's disclosure of his office affairs. Shargel declined to describe what Halderman had found; his court filing noted only that Letterman himself described his conduct with female employees as "creepy."

Letterman's lawyer strove to keep the focus on the extortion case, not the comic's liaisons, but added that no one has ever made a formal sexual harassment claim against him.

"His conduct's not an issue here," Horwitz said after the brief court session.

Letterman is prepared to testify against Halderman if the case goes to trial, Horwitz said.

Halderman, wearing a gray suit, pinstriped shirt and green tie, declined to comment.

The 51-year-old producer for CBS' "48 Hours Mystery" has pleaded not guilty. He could face five to 15 years in prison if convicted.