Casablanca Car

Ok I remember the story completely. There is a little boy who's dad is a milkman. While delivering milk early one morning they witness a car go over a cliff into a deep lake. The father jumps in only to find the driver is naked, handcuffed to the steering wheel and has been beaten to death. The book follows the story of this boy as he tries to find out who killed the man in the car. There are several eccentric characters such as the piano teachers Ms green glass and Ms blue glass. There is a black woman named "The Lady" who communicates with a river monster and can interpret dreams. And in the end it is the local veterinarian, an ex nazi, who is found to be killing.

I know the title has something to do with "Boy"
I also know that Richard Thomas I from the waltons read for the audio book version.

Please help.
I just found it!! It's "Boy's Life" Thanks for the try though