Scratch is a term that law enforcement uses for the notes that they take. They are informal and much like the notes and lists we make for ourselves, they can be on a variety of different types of paper written with whatever writing implement we have handy, with our own abbreviations.
Some of the notes in the pdf are hard to read and decipher, I haven't quite figured all of them out. The notes do offer a look at the steps LE takes to develop leads to further the investigation. Not all leads pan out and some are bogus.
I will be posting the scratch over the next few weeks in small batches. If you look at it all at once, it's just too overwhelming.
On page 20 of the file there is mention of Bill Vance and Topanga Stables, it's something about a car given to the owner of the stables and Bill wanting the car back so he can start a church as near as I can tell.
I did a search on Topanga Stables and found that Phil and Karen Schoonmaker owned it. In 1968 there were ads in the local newspaper for horses that were for sale at the stables.
In September of 1969 Phil Schoonmaker received a Distinguished Service Citation from LASD for aiding in the arrest of arsonists.
Topanga Stables was a place where the public could go on trail rides much like Spahn Ranch. This is a portion of an article about the different places to go trail riding in LA.