In CA, if you have documented illegal activity by your employer, you may contact the Department of Fair Employment and Housing. Illegal activity would have to fall under a protected class or protected employee activity.
You have to remember, that HR is going to scream the loudest about these things, because ultimately, they are the one's on the hook for anything illegal happening. If they refuse to investigate or threaten to take any adverse employment against you for complaining, they can be held liable for retaliation and failure to stop illegal employment activities in the workplace.