Dirt (1996) is the 2nd novel in the Stone Barrington series. 

Quite good. As was the first, New York Dead.

When poison-pen columnist Amanda Dart herself becomes the victim of an anonymous gossipmonger, she enlists the help of New York P.I. Stone Barrington to uncover the culprit, someone out to expose the peccadilloes of other influential gossip columnists, as well.

Dirt is the title of a faxed newsletter focused on dishing the dirty secrets of gossip columnists. An interesting premise.

Plenty of sex in this book, as there was in the first.