The former Internal Revenue Service official at the heart of the agency's tea party scandal once again refused to answer questions at a congressional hearing Wednesday that quickly devolved into political bickering between Democrats and Republicans.

Lois Lerner headed the IRS division that improperly targeted tea party and other conservative groups for extra scrutiny when they applied for tax-exempt status during the 2010 and 2012 elections. She was the first IRS official to publicly disclose the targeting, issuing an apology on behalf of the agency at a law conference in May 2013.

But when she was called to testify before the House Oversight Committee a few days later, she invoked her Fifth Amendment right not to incriminate herself. Committee Chairman Darrell Issa recalled Lerner for a hearing Wednesday.

Lerner appeared with her lawyer, but she invoked the Fifth Amendment at least nine times when questioned by Issa.

(Watch: IRS scandal: Lois Learner retires)

Issa, a California Republican, quickly adjourned the hearing despite attempts by Rep. Elijah Cummings, the top Democrat on the committee, to make a statement. At one point, Issa said, "Shut it down," and Cummings' microphone was turned off.

Afterward, Cummings, of Maryland, said he wanted to point out that despite Republican claims of a political conspiracy, the committee's investigation so far has not shown any political motivation by IRS agents.