Complex sentence: Niebaum admits that he took bribes from the guilty parties to cover up their crimes, and he implicates many of Roman's squad mates in the conspiracy but does not know who the ringleader is.
Split into simpler sentences: Niebaum admits that he took bribes from the guilty parties to cover up their crimes. Niebaum implicates many of Roman's squad-mates in the conspiracy, but does not know who the ringleader is.