WASHINGTON — A Justice Department investigation into the Internal Revenue Service has expanded to include an inquiry into the disappearance of e-mails from a former senior IRS official.

Deputy Attorney General James Cole was to update Congress today about the department’s investigation into whether the agency targeted conservative groups seeking tax-exempt status. He also was expected to tell members of the House Oversight and Government Reform Committee that investigators now were looking into e-mails that went missing from the computer of Lois Lerner, who headed the IRS division that deals with tax-exempt organizations.

The IRS has said it lost the e-mails in 2011 when Lerner’s computer crashed.

Lerner has become a central figure in several congressional investigations into the handling of applications for tax-exempt status by tea party groups.

The disclosure by Lerner in May 2013 that the IRS had engaged in “inappropriate” targeting of conservatives set off a political firestorm.