The Manhattan district attorney has confirmed that a CBS News employee has been indicted in connection with an alleged plot to extort US$2 million from late-night talk show host David Letterman.

Letterman revealed the existence of the plot at the taping of his Thursday night show, telling his audience that a man had threatened to reveal that the talk show host had engaged in sexual relationships with women who worked on his show.

The 62-year-old comic told his audience that he recently found a package in his limousine that contained a letter indicating that a man had proof of his affairs.

"I know that you do some terrible, terrible things and that I can prove that you do some terrible things," Letterman told his talk show audience, when explaining the contents of the letter.

The talk show host acknowledged that the letter contained proof.

Through a lawyer, Letterman set up a meeting with the man, who told the talk show host that he would write a book and screenplay if he was not paid off.

Two more meetings followed and Letterman wrote a fake $2-million cheque, as part of a police investigation. An arrest soon followed and Letterman testified before a grand jury.

Letterman told his talk show audience that he admitted to the affairs during his grand jury testimony. But he did not provide details on when they occurred.

"I was worried for myself, I was worried for my family," Letterman said. "I felt menaced by this, and I had to tell them all of the creepy things that I had done."

He said "the creepy stuff was that I have had sex with women who work for me on this show. My response to that is yes, I have. Would it be embarrassing if it were made public? Yes, it would, especially for the women."

Letterman said it would be at the women's discretion if they chose to reveal the relationships and that he felt it was necessary to protect them and his own family.

D.A. gives details

At a Friday morning news conference, District Attorney Robert Morgenthau said that Robert J. Halderman -- an Emmy-nominated producer who works on the true-crime TV show "48 Hours" -- had been arrested and indicted on one count of attempted first-degree grand larceny.

Halderman, 51, entered a not guilty plea as he was arraigned on an attempted grand larceny charge, and was released on $200,000 bail. He was also suspended from his duties at CBS.

If convicted, Halderman faces five to 15 years in prison, Morgenthau said.

"The message of this case is that New York will not tolerate the coercion or extortion of anyone, be a victim rich or poor, famous or anonymous," Morengthau said Friday.

Morgenthau provided a few additional details on the alleged plot, including the fact that Letterman and his lawyer worked with the District Attorney's Office to collect evidence for the case.

Letterman's lawyer taped two conversations with the accused, Morgenthau said, one of which took place Sept. 23, the other on Sept. 30.

The accused received the cheque from Letterman at the Sept. 30 meeting and he deposited it at a Connecticut bank the next day.

A search warrant was later executed at Halderman's Connecticut home, Morgenthau said.

Morgenthau said he did not want to disclose the name of Letterman's lawyer "at this moment."

"He's a West Coast lawyer, nobody we know here in New York," Morgenthau said.

He declined to give details on the specific nature of the threats and materials that Letterman received.

"Letterman gave a pretty accurate description of what was in the material and there will be further discussion of that in the arraignment," Morgenthau said

The alleged extortion plot is not the first time that the well-known Letterman has been targeted.

In 2005, Letterman was the victim of a plot to kidnap his nanny and son for a US$5 million ransom.

Letterman married his long-time girlfriend, Regina Lasko, earlier this year. They had been dating since 1986.

The couple have a young son, Harry, who will turn six years old next month.

With files from The Associated Press