The Treasury Department’s inspector general is examining whether political considerations interfered with Secretary Steven Mnuchin’s promised analysis of the Republican tax proposal.

“It’s a top priority,” Rich Delmar, counsel to inspector general Eric Thorson, said Thursday in an email. Delmar said he could not provide a timeframe for when the inquiry would be complete because it would depend on how quickly the department’s official watchdog receives the information and “how complex issues are.”

In a letter early on Thursday, Senator Elizabeth Warren asked Thorson’s office to review whether Treasury resources were used to research the tax plan, and why no analysis has been released to the public or Congress. Mnuchin has repeatedly pledged that the Republican proposal would pay for itself through economic growth, and that his department would provide detailed analysis to support those statements.

But, with the Senate preparing to vote on the tax overhaul this week, Mnuchin has yet to deliver the analysis.

“Either the Treasury Department has used extensive taxpayer funds to conduct economic analyses that it refuses to release because those analyses would contradict the Treasury Secretary’s claims, or Secretary Mnuchin has grossly misled the public about the extent of the Treasury Department’s analysis,” Warren, a Democratic Senator from Massachusetts, wrote in the letter.

A Treasury spokeswoman didn’t immediately respond to a request for comment.

A new analysis released Thursday by the Joint Committee on Taxation found that the Senate tax bill would generate enough economic growth to lower its $1.4 trillion revenue cost by about $458 billion over a decade. That would leave a 10-year revenue loss of roughly $1 trillion, said the JCT, Congress’s official scorekeeper on tax legislation.

Mnuchin has promised “complete transparency” about the analysis and the tax plan’s economic benefits. However, in September, The Wall Street Journal reported that Treasury had removed from its website a 2012 research paper that contradicted the Trump administration’s stance on the wage growth expected from a corporate rate tax cut.

Warren, whose letter followed a New York Times report on Thursday that Treasury hadn’t completed the analysis Mnuchin had touted, asked the inspector general to review whether the department’s resources were used to undertake a tax plan analysis, if the research was conducted using Treasury standards and protocols, whether there was any political interference, and the reasons why findings weren’t released to the public or Congress.

“I’m glad @USTreasury’s IG responded quickly to my request,” Warren tweeted late Thursday.

Bloomberg