What can be done to a landlord that takes money from people that arent on leases and neva will be?

I have been stayin in theses apartments for a while now!I kno of several people that pays her that are not on any lease wat so ever.she has changed paperwork altered doents and all kinda illegal sht.the f.b.I. have came and investigated her *** and act like they can't do sht bout it.what if anything can be done bout her ***?