More than a dozen Senate Democrats have asked the inspectors general at the Commerce Department and the Department of Justice to review new claims, made in the census citizenship question case, about the political motivations behind adding the question.

The letter, whose signatories include Minority Leader Chuck Schumer (D-NY), requests that the inspectors general investigate efforts by the administration to conceal the role played by a now-deceased GOP gerrymandering guru in getting the question added to the 2020 census.

The redistricting expert, Thomas Hofeller, helped write a draft for the formal DOJ request that the question be added to the 2020 census, according to documents put forward by the legal challengers Thursday. That draft was passed along to then-DOJ civil rights head John Gore, who authored the final request submitted to the Census Bureau. The challengers on Thursday also made public for the first time a secret 2015 study Hofeller wrote that said a citizenship question would be needed to undertake a redistricting overhaul that would boost the electoral advantages of “Republicans and Non-Hispanic Whites.”

The rationale put forward by the Justice Department in its official request — as well as the one that Hofeller wrote for the draft request passed to Gore — was that data from the question would enhance Voting Rights Act enforcement.

Gore and Mark Neuman, an outside advisor who gave Gore the draft request, have both been accused by the challengers of lying in depositions for the case.

The Justice Department has denied that Gore lied or that the formal DOJ request was based on Hofeller’s study. The Department, however, has not disputed that Neuman passed the draft along to Gore — which Gore revealed in a congressional interview only after the case was decided at the trial court — or that parts of that draft were written by Hofeller.

Neuman, likewise, has denied giving false testimony, but hasn’t addressed the claim that Hofeller partially wrote his draft. Neuman denied being part of the request draft process in his deposition and did not disclose Hofeller’s involvement in helping craft his draft of the request.

Read the letter the below: