Irs Investigations -- NPR's Jon Greenberg reports that the acting commissioner of the IRS will appear today before the Senate Finance Committee. The Senators have been investigating charges of mismanagement and abusive practices by the agency. A current IRS agent testified that supervisors directed her to perform unnecessary audits on low-income taxpayers. She also said that the IRS gave rewards to agents who offered fabricated evidence against their collegues. Others testified that the agency targeted taxpayers who were unlikely to resist, or who would back down when faced with legal fees.