The Treasury Department’s internal watchdog said Monday it would review why a new $20 bill featuring the abolitionist Harriet Tubman has been delayed by the Trump administration.

In a letter to Senate Minority Leader Chuck Schumer (D-N.Y.), the acting inspector general of the Treasury, Rich Delmar, said his office would open an inquiry into the delay amid widespread outcry from lawmakers. The review will be included as part of an audit that was already scheduled by the inspector general.

The Treasury Department has been working on the redesign since it was first announced in 2016 by the Obama administration, and had hoped to unveil the new bill in time for this year’s 100th anniversary of the 19th Amendment, which gave women the right to vote.

But those plans came to an abrupt halt last month after Treasury Secretary Steven Mnuchin said during a congressional hearing that the new $20 bill wouldn’t be finished until 2026, after President Donald Trump leaves office. He said the bill likely wouldn’t be in circulation until at least 2028.

Delmar said his office would question those involved in the new design process, including Treasury executives and members of the Bureau of Engraving and Printing, which produces American currency.

“If, in the course of our audit work, we discover indications of employee misconduct or other matters that warrant a referral to our Office of Investigations, we will do so expeditiously,” Delmar wrote. He said the investigation would take about 10 months.

Schumer last week called on the Treasury’s watchdog to determine why the bill had been delayed for so long, saying Mnuchin’s explanation that the department was instead focusing on enhanced anti-counterfeiting measures for other bills wasn’t believable.

“The motivation for the Trump administration’s decision to delay the release of the new note has not been credibly explained, and the inspector general’s review must get to the bottom of this,” Schumer said in a statement to Politico.

The Treasury Department issued a statement saying any scheduling changes surrounding the issuing of new banknotes was not political but rather reflected the need to design security features to prevent counterfeiting.

“The timeline for issuing new notes is not a political process, and the timeline for issuing a new $20 note remains consistent with the prior Administration’s,” the department said in a statement. “As the Department and Bureau of Engraving and Printing have consistently stated, the only consideration with regard to the redesign schedule of our Nation’s currency has been security and potential counterfeiting threats.”

Trump himself has at times lambasted the Tubman bill, calling the change “pure political correctness” while celebrating President Andrew Jackson — a slaveholder and the current face on the $20 — as someone with a “great history.” If Tubman is eventually placed on the $20 bill, she would be the first woman on an American bill since Martha Washington, and the first ever African American.

Earlier this month, a preliminary design of the new bill was leaked to The New York Times. The outlet noted that “extensive work” had already been done.

This article has been updated with a statement from the Treasury Department.