NEW YORK - CBS said this morning that an employee had been charged with attempted grand larceny in an investigation involving "Late Show" host David Letterman, who told his TV audience last night that he had sexual relationships with female employees and that someone had tried to extort $2 million from him over the affairs.

CBS said the employee worked on "48 Hours" and has been suspended pending the results of the investigation. The network said the employee was arrested yesterday, hours before Letterman went public with his account during a taping of his late-night show in New York.

The network said it was cooperating with authorities.

During the taping, Letterman discussed receiving a threat to either pay $2 million or risk the relationships being made public.

In a release from the show's production company, Letterman said that he had referred the matter to the Manhattan District Attorney's Office and that an investigation ended in an arrest. Letterman did not identify the person he said had been arrested.

As part of the investigation, Letterman said he issued a "phony" $2 million check to the individual and the arrest followed - along with testimony by Letterman.

"This morning, I did something I've never done in my life," Letterman said on his show. "I had to go downtown and testify before a grand jury."

It was not clear when the relationships took place. Letterman and longtime girlfriend Regina Lasko married in March. The couple began dating in 1986 and have a son, Harry, born in November 2003.

"My response to that is, yes I have," Letterman said. "Would it be embarrassing if it were made public? Perhaps it would. I feel like I need to protect these people. I need to certainly protect my family."

CBS spokesman Chris Ender said yesterday that "Letterman's comments on the broadcast tonight speak for themselves."

It's the second set of embarrassing headlines for Letterman in four months.

In June, he apologized to Sarah Palin for making a crude joke about the former Republican vice presidential candidate's 14-year-old daughter.

Although there was a small "fire Letterman" demonstration outside of his studio later, CBS stood by its late-night star.

After nearly 15 years in second place to NBC's Jay Leno in the ratings, Letterman took over the top spot this summer, after Conan O'Brien became "Tonight" show host.

Letterman's CBS "Late Show" has been on the air since 1993 and before that, he had a late-night show on NBC.

Alicia Maxey Greene, a spokeswoman for the Manhattan D.A., declined to comment.