House Speaker John Boehner (R-Ohio) said in an interview aired late Wednesday that it's "inconceivable" someone didn't inform President Obama about the IRS's targeting of conservative groups.

"It's pretty inconceivable to me that the president wouldn't know," Boehner said in an interview with Fox News Channel's Greta van Susteren. "I'm just putting myself in his shoes. I deal with my senior staff every day. And if the White House had known about this, which now it appears they've known about it for about a year, it's hard to imagine it wouldn't have come up in some conversation."

Boehner acknowledged that the White House aides who knew might have deliberately not told Obama but again said that was "inconceivable." He also accused the administration of "an arrogance of power."

"They could have attempted to insulate the president from this news," Boehner said. "But with as many people that were involved in the audit, the number of people involved in the investigation, somebody -- and the number of people in the White House that knew -- it really is inconceivable that he wouldn't have known about it."

A week ago, Obama said clearly that he "did not know anything about the [inspector general] report before" it was released. Over the weekend, White House senior adviser Dan Pfeiffer said that no one in the White House knew about the investigation until last month and didn't know the details of it until last week.

By Monday, though, the White House acknowledged that the White House counsel's office knew about the thrust of the investigation and had shared information about it with White House chief of staff Denis McDonough.

By Wednesday, White House press secretary Jay Carney acknowledged the inconsistencies in the administration's disclosure, but the White House continues to say Obama was deliberately shielded from knowledge about the IRS scandal.

Boehner says the White House knew of the targeting last year, but he appears to be referring to Deputy Treasury Secretary Neal Wolin, who isn't technically in the White House but is a political appointee. Wolin, who knew of the probe but not the findings, testified Wednesday that he didn't inform either the White House or the Obama campaign of the audit.