Since you asked, here is contact information for several local Federal Bureau of Investigation offices. FYI, numerous county officials have contacted the Riverside FBI office, interviewed with them, and have requested investigations into wrongdoing in San Bernardino County. So far, nothing concrete has happened. Because so many have already contacted that particular office, I would tend to think they could also stand to hear from some private citizens.
Los Angeles: (310) 477-6565
Riverside: (951) 686-0335
Victorville: (760) 951-7119
If you want to complain or offer evidence about wrongdoing, cover ups, Medi-cal and 1011 fraud at Arrowhead Regional Medical Center specifically, you need to contact the United States Department of Justice at (202) 616-2492, as that investigation is already ongoing.