A top IRS official in the division that reviews nonprofit groups will invoke the Fifth Amendment and refuse to answer questions before a House committee investigating the agency’s improper screening of conservative nonprofit groups.

Lois Lerner, the head of the exempt organizations division of the IRS, won’t answer questions about what she knew about the improper screening – or why she didn’t reveal it to Congress, according to a letter from her defense lawyer, William W. Taylor 3rd.

Lerner was scheduled to appear before the House Oversight committee Wednesday.