Milk and Honey is a 1990 novel by Faye Kellerman, published by William Morrow and Company as part of the Peter Decker/Rina Lazarus series.
Pete also finds himself posting bail for an old Army buddy of his (Abel Atwater), who had been charged with rape and assault.
While backtracking clues in the found toddler's case, he finds the family home is the site of a quadruple murder, and that her name is Katie Darcy.
Decker has to slog through many peripheral clues in the case, including a biker bar and a backwoods section of Los Angeles County.
His partner Marge Dunn ends up dealing further with one of Katie's potential parents, whose own child was kidnapped in a custody case.