The Treasury Department’s internal watchdog said it will look into why a previously agreed-to redesign of the $20 bill featuring abolitionist leader Harriet Tubman will not be unveiled next year. Treasury Secretary Steven Mnuchin came under fire after announcing last month that he was delaying plans to replace Andrew Jackson’s portrait on the $20 bill with Tubman. Under a 2016 Obama initiative, Tubman was originally scheduled to replace slaveholder Andrew Jackson by 2020—the 100th anniversary of women being granted the right to vote. Harriet Tubman would be the first woman in over a century and the first African American to appear on the front of a U.S. banknote.