The Treasury Department will conduct an investigation into the circumstances leading to a delay in the production of a new $20 bill featuring a portrait of slave-turned-slave-emancipator Harriet Tubman.

In a letter to Sen. Chuck Schumer, D-N.Y., released Monday, acting Inspector General Rich Delmar explained the inquiry will be folded into a larger examination of the Bureau of Engraving and Printing’s project management processes for new note design that was already in the works.

“As part of this work, we will interview the stakeholders involved in the new note design process,” Delmar wrote.

In 2016, the Treasury Department announced it would replace President Andrew Jackson’s face with that of the famed abolitionist by 2020. As NPR reported, the update would have made Tubman the first woman since Martha Washington to appear on an American currency note and the first ever African American. But last month, Treasury Secretary Steven Mnuchin announced the redesign will be delayed until 2028.

Schumer called on the department to launch an investigation last week, specifically asking for a review of “the involvement of other participants in the interagency process related to the redesign – including the Secret Service, Federal Reserve, and the White House – to ensure that political considerations have not been allowed to infect the process for designing American currency.”