For months, good-government groups and some Democratic lawmakers have been calling on Treasury Secretary Steve Mnuchin to recuse himself from matters related to the federal investigation into Russian election meddling. Mnuchin’s role as finance chair of Donald Trump’s 2016 campaign means he can’t impartially oversee a probe that delves into Trump associates’ financial affairs, they have argued.

Those calls took on a new urgency this week when The New Yorker revealed that Suspicious Activity Reports (SARs) filed on long-time Trump fixer Michael Cohen were removed from a database kept by the Treasury Department’s Financial Crimes Enforcement Network (FinCEN) division.

Their absence, which is highly unusual, so alarmed a longtime law enforcement official that he or she leaked some of the documents to the press out of concern that information was being intentionally withheld from law enforcement.

In multiple letters sent since late 2017, Democratic lawmakers have asked Mnuchin to recuse himself from the Russia probe, and to detail any information Treasury has received about potential illegal activities by Trump and his associates.

“Have you ever directed, or has any other Trump administration official, Trump campaign official, or Trump family member called on you to direct U.S. Treasury officials or staff members to obscure, destroy, or withhold information implicating the president, Trump campaign officials, Trump family members, or his associates?” the Democrats wrote in January.

They received no response from Mnuchin.

Appearing on MSNBC Wednesday night, one of the Democrats, Rep. Maxine Waters of California, said the reported removal of the SARs from the Treasury database underscores the need for Mnuchin to provide answers.

“Someone removed this information, and the Treasury Secretary is going to have to answer for this,” Waters said. “The question is, why did he ignore us?”

In December, progressive groups noted in their own letter to Treasury’s Inspector General that Mnuchin had replaced the director of FinCEN with his own choice, just days after former Trump campaign chair Paul Manafort was indicted for money laundering and a host of other financial crimes.

The groups called the timing “extremely worrisome,” and asked the IG’s office to look into whether Mnuchin should recuse, a request the IG declined.

On Thursday, Citizens for Responsibility and Ethics in Washington filed a complaint with the Treasury Department Inspector General asking for an investigation into the “possible compromise” of information in the database.

Sources familiar with FinCEN’s database told the New Yorker they could have been removed by a request from the special counsel’s team or from federal prosecutors who are investigating Cohen for financial crimes.

The Treasury Department did not immediately respond to TPM’s request for comment. In a Thursday afternoon statement, a FinCEN spokesperson said that they do sometimes limit access to SARs in ongoing investigations.

New statement from FinCEN spox – it does limit access to SARs in ongoing investigations pic.twitter.com/aoeAwggB34 — Aruna Viswanatha (@aviswanatha) May 17, 2018

This post has been updated.