Washington • The Justice Department won't seek criminal contempt charges against Lois Lerner, the former IRS official at the center of a controversy over how the IRS treated conservative political groups.

Ronald Machen, the outgoing U.S. attorney for the District of Columbia, announced the decision in a letter Tuesday to House Speaker John Boehner, which was made public Wednesday.

The GOP-controlled House had referred the case to federal prosecutors after lawmakers voted last year to hold Lerner in contempt of Congress for her refusal to testify before a pair of committee hearings.

Lerner directed the IRS division that processes applications for tax-exempt status. She set off a political firestorm in 2013 when she disclosed that agents had improperly singled out applications from tea party and other conservative groups for extra, sometimes burdensome scrutiny.