Did late night talk show kind David Letterman have an adult relationship with his favorite assistant?

One of the women at the center of the David Letterman alleged extortion case is Stephanie Birkitt, former assistant to the CBS Late Show host, according to a search warrant obtained by FOX 5 New York. And get this — Birkitt is the live-in girlfriend of the suspect arrested Thursday. Birkitt was a regularly featured on the Late Show, in taped segments.

CBS News employee Joseph Robert Halderman, a 51-year-old producer of 48 Hours, is accused of trying to extort $2 million from Letterman. He is now charged with attempted grand larceny.

Halderman sent Letterman a package which allegedly included treatments for a screenplay with supporting materialsThe warrant goes on to say the “supporting materials” included copies of parts of a diary and correspondence belonging to Birkitt, letters, emails, and photos.

Letterman acknowledged on his show last night he had sex with several female members of his staff.