Felix Gillette reports in the NY Observer that the CBS News investigative unit is following through on claims that it would look into the David Letterman/Joe Halderman saga:

On Oct.3, two days after news broke of the alleged blackmail attempt of David Letterman by 48 Hours producer Joe Halderman, CBS Evening News executive producer Rick Kaplan told The Washington Post that the network would be reporting the story as though it were a scandal in the Commerce Committee. Afterward, TV news veterans were skeptical. But, according to The Observer’s sources, [Armen] Keteyian and his team of producers are actively investigating the love triangle gone horribly awry between the CBS Late Show host; his former employee Stephanie Birkitt; and the suspended-with-pay Mr. Halderman.

Former CBS News correspondent Dr. Bob Arnot told the Observer, “From having talked to some friends there, who are pretty highly placed, they really want to hit this story hard, like any other journalistic story.”

A CBS spokesperson declined to comment to TVNewser on the report.