WASHINGTON (AP) — Senior Treasury officials were made aware in June 2012 that investigators were looking into complaints from tea party groups that they were being harassed by the Internal Revenue Service, a Treasury inspector general said Friday, disclosing that Obama administration officials knew there was a probe during the heat of the presidential campaign.

J. Russell George, the Treasury inspector general for tax administration, testified alongside ousted IRS head Steven Miller, who did little to subdue Republican outrage during hours of intense congressional questioning. Both defiant and apologetic, Miller acknowledged agency mistakes in targeting tea party groups for special scrutiny when they applied for tax-exempt status, but he insisted that agents broke no laws and that there was no effort to cover up their actions.