WASHINGTON ― Democrats have told a U.S. district court that they have evidence that somebody might have interfered with an audit of President Donald Trump’s tax returns ― but they’re still not sharing any details publicly.

The House Ways and Means Committee is suing the Trump administration for copies of his returns, saying they need to make sure the Internal Revenue Service is properly enforcing tax laws against the president.

The committee’s attorneys told U.S. District Judge Trevor McFadden in a brief last month that since they filed the suit, a government employee has come forward with “evidence of possible misconduct” and potentially “inappropriate efforts to influence” the president’s audit.

The IRS has audited the sitting president and vice president every year since Richard Nixon got caught underpaying his taxes in the 1970s. Democrats now argue that they need to check that this mandatory audit is done properly.

Ways and Means Chair Richard Neal (D-Mass.) told HuffPost on Tuesday that “legal considerations” prevent him from talking about the whistleblower’s material, which Democrats offered to share with Judge McFadden in private.

“It was volunteered, it wasn’t solicited,” Neal said of the new evidence. “Other than that, I think I probably want to refrain from any talk on that.”

Democrats had hoped the whistleblower would bolster their argument for speeding up the case, but McFadden denied their motion to expedite the proceedings. It’s unclear if he’s taken the committee up on its offer to share details.