(Washington, DC) -- Former IRS official Lois Lerner is again refusing to testify about IRS targeting of conservative political groups for extra scrutiny.

In a hearing of the House Oversight Committee, Lerner repeatedly cited her constitutional rights and refused to answer questions. It was the second time she has refused to testify before the House panel. The IRS flap prompted a shakeup at the tax collecting agency.

Democrats insist liberal groups were also targeted for additional scrutiny.