The U.S. Treasury's Office of the Inspector General will review the delay of a new $20 bill design featuring abolitionist hero Harriet Tubman, acting Inspector General Rich Delmar said in a letter released Monday.

"As part of this work, we will interview the stakeholders involved in the new note design process," Delmar wrote to Sen. Charles Schumer, D-N.Y.

The Tubman redesign was initially scheduled for 2020 and coincided with the 100th anniversary of the 19th amendment which gave women the right to vote.

But Treasury Secretary Steven Mnuchin said last month that the redesign would be delayed so the $10 bill and the $50 bill could be redesigned first to make it harder for the bills to be counterfeited. He said those bills will be introduced before a redesigned $20 bill.

A Treasury Department spokesperson said in an emailed statement that process of issuing a new bill is not political. The security of the currency and combating counterfeiting are the only concerns considered in the redesign schedule, the statement says.

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The Office of the Inspector General said their audit will be looking into security measures at the Bureau of Engraving and Printing. The effort is expected to take 10 months, according to the letter.

On June 19, Schumer asked the office to investigate whether the delay was driven by political reasons.

Schumer said in a news release that he is pleased the Treasury Department is looking into the issue.

“There are no women, there are no people of color on our paper currency today, even though they make up a significant majority of our population, and the previous administration’s plan to put New Yorker Harriet Tubman, on the $20 note was a long overdue way to recognize that disparity, and rectify it,” he said.

Follow Elinor Aspegren on Twitter: @elinoraspegren.

Contributing: The Associated Press