Records re Al Capone

I’m seeking information about Al Capone’s business/real estate transactions in Southern California, circa 1929-1931. FBI, IRS, and courts undoubtedly all generated relevant records. I’d rather not travel across the country to do this research, but if I have to (or if I hire someone), it would help to know where the records might be and how to access them. I'd greatly appreciate any help or suggestions. Thanks!

CJ