Investigating the murder of evangelist Persis Magen's right-hand woman, Cat DuBois, Joe and Tommy meet a variety of people of varying degrees of weirdness. The Phoenix Zoo depiction in the denouement is as it was during its first few years (I am a charter member). It is sort of the same today only much, much better.
Used availability for Sandy Dengler's Cat Killer
December 1993 : USA Paperback
May 2014 : USA, Canada, UK Kindle edition