Cash-poor Texas dog-trainer Katherine Driscoll, threatened with foreclosure on her kennel but offered a $100,000 bailout by her long- estranged father, Lester Renfro, arrives at the Austin zoo where he works just hours after he's clawed to death by a tiger. A locker key that Renfro sent her sets her on the trail of a long-range scheme to defraud a zoo trust set up by her well-heeled grandmother; meantime, somebody calling himself the ``pointman'' is sending threatening letters to Kate and others and setting up bogus animal-killings of the recipients. As she settles into a despised new job among the zoo's reptiles, Kate wonders where Renfro, long cut off from his wife's wealthy family, expected to get the money he promised Kate; what secret he planned to cut her in on; and whom she can trust among the human inmates in the zoo. Colorless suspects but striking zoo background and a most appealing heroine. Too bad first-novelist Walker seems determined to make this Kate's last case.