John Augustus Sutter historical records in California

Hi all,

I've been reading about John Augustus Sutter, the (in)famous settler who came to California before the Gold Rush. After his departure from Switzerland, he crossed the United States until he reached California. There are a few accounts of his participation in slavery and the abuse of Native Americans sourced in this article. However, most of the allegations come from a single one of Sutter's employees, Heinrich Lienhard. This documentation also hints at prior similar behavior from Sutter, notably during his time in Santa Fe. I was wondering where I would begin to look for additional testimony to his actions during his early time in California and before. He stayed in Hock Farm after California joined the Union in 1850, but I'm guessing by then most of the documentation available is related to his well-known legal battles to reclaim his lost "New Helvetia" (he even ran for first Governor of California in 50), which is less of interest to me.

What kind of archive would I need to look into to get a better sense of the prevailing behavior of settlers towards Native Americans in California in general during that time, and testimony regarding John Sutter in particular? How would such accounts be documented?

Thank you for any suggestions you may have

Best regards,

Mehmet