In their letter to Chairman Patrick Leahy (D-VT), the Judiciary Republicans quoted from Adams' testimony this month in front of the Commission on Civil Rights.
"If these alarming allegations are true, the Civil Rights Division is actively engaged in widespread politicization and possible corruption," the letter read.
The commission, which is controlled by conservatives, has been investigating the NBPP case since last fall.
The case has gotten widespread attention recently on conservative blogs and in the mainstream media after Adams -- who had a role in the U.S. attorney firings -- testified and appeared several times on Fox News.
But, as Greg Sargent points out, the Judiciary Committee already investigated this very case back in April.