The Treasury Department's inspector general is investigating whether Treasury Secretary Steven Mnuchin Steven Terner MnuchinShutdown clash looms after Democrats unveil spending bill Lawmakers fear voter backlash over failure to reach COVID-19 relief deal United Airlines, unions call for six-month extension of government aid MORE let politics affect his promised analysis of the GOP's plan to reform the tax code.

Bloomberg News reports that Inspector General Eric Thorson is looking into whether Mnuchin is refusing to release the Treasury Department's analysis of the tax plan that passed the Senate Budget Committee in a 12-11 vote on Wednesday because the agency's report contradicts claims made by both the secretary and Republicans in Congress.

“It’s a top priority,” Thorson's counsel, Rich Delmar, told Bloomberg.

ADVERTISEMENT

The move comes after Sen. Elizabeth Warren Elizabeth WarrenJudd Gregg: The Kamala threat — the Californiaization of America GOP set to release controversial Biden report Biden's fiscal program: What is the likely market impact? MORE (D-Mass.) accused Mnuchin in a letter to Thorson of using taxpayer funds to conduct an analysis that the government was now refusing to let see the light of day.

“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 wrote in her letter.

Thursday night, Warren responded to the inspector general's investigation on Twitter, questioning whether Mnuchin "misled the public" about the GOP's tax plan.

"I’m glad @USTreasury's IG responded quickly to my request. Either Treasury used taxpayer funds to conduct analyses it won’t release because they contradict Mnuchin’s claims that this bill grows the economy, or Mnuchin misled the public about the analysis," the senator tweeted. "Either is a big problem."

I’m glad @USTreasury's IG responded quickly to my request. Either Treasury used taxpayer funds to conduct analyses it won’t release because they contradict Mnuchin’s claims that this bill grows the economy, or Mnuchin misled the public about the analysis. Either is a big problem. https://t.co/56HWdgvO3S — Elizabeth Warren (@SenWarren) November 30, 2017

The Senate is poised to vote on the GOP's tax proposal this week. Republicans are hoping to send a bill to President Trump's desk by the end of December, after the House passed a similar bill in a 227-205 vote earlier this month.