Hangman, by Faye Kellerman

Peter Decker and Rina Lazarus's daughter--the fourth of their "combined" brood--is about to leave home. So, in Hangman, Faye Kellerman decides to give them a "new" child, Gabe--the 14-year-old son of two characters from a previous installment in the series. The disappearance of Gabe's mother is one of two major subplots in this mystery. The second is the murder of a young woman with a night life at odds with her work as a dedicated nurse in the neonatal unit of St. Tim's hospital. That murder eventually leads the homicide squad to two serial killers.

Hangman is a decent mystery--not terribly suspenseful, but interesting enough to keep me reading.