I guess I'll have to do a search just in LA County only. Of course, LA County ain't the end all to be all.
I'm pretty sure it's DOJ. I seem to remember digging it up years ago for some Liberal on another board.
The stats are also part of House Judiciary Subcommittee testimony. Here: http://www.manhattan-institute.org/html/mac_donald04-13-05.htm
I doubt they made this stuff up.