Complex sentence: The main political action committee (PAC) supporting the bond was accused of having a conflict of interest because it received over US $100,000 in contributions from contractors and equipment suppliers for METRORail who stood to gain financially from its expansion.
Split into simpler sentences: The main political action committee (PAC) supporting the bond was accused of having a conflict of interest due to the relationship between its main contributors and METRO. The PAC received over US $100,000 in contributions from contractor firms and equipment suppliers for METRORail who stood to gain financially from its expansion.