who do you call when you suspect someone of nursing home abuse?

I suspect that my Girlfriends mother is abusing the elderly residents at the nursing home she works at. Not only that I think she might be stealing medication from the nursing home to feed her and her husbands rather large drug habit.
I don't know if i should call the police or not
My Girlfriend is estranged from her mother, so i don't know the name of the nursing home. but some stuff has been going on, and my girlfriends grandfather said something along the lines of she molests the older people... what can i do?

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