House Ways and Means Committee Chairman Dave Camp told CNBC ahead of his panel's IRS scandal hearing on Friday that he wants to know who "hatched" the plan to target conservative groups seeking tax exempt status for extra scrutiny.
"The scale of it and the length of time, this was a pattern. This was a culture of discrimination where it was OK to go after conservative groups," the Michigan Republican said in a "Squawk Box" interview. "[But] progressive groups seemed to find the process just worked OK for them. That's what's troubling."
(Read More: Stop 'Rot', Abuse at IRS: Rep. Boustany)
Another member of the panel, Democratic Rep. Charles Rangel of New York, also appeared on the show, saying any talk of impeachment of President Barack Obama over this is "ridiculous."
"This is embarrassing for the president, but he's doing everything he can do," Rangel said. "In a bipartisan way, we want to see how this got started, and cut this cancer before it spreads."