This is book number 3 in the Cat Who... series.
When Qwilleran decides to do a feature story on Junktown, he gets more than he bargained for. Not the dope den he anticipated, Junktown is a haven for antique dealers and collectors—as strange a lot as the crafty reporter has ever encountered. When a mysterious fall ends the career—and the life—of one of Junktown's leading citizens, Qwilleran is convinced it was no accident. But, as usual, it takes Koko to prove he's right.