As Congress adjusts its expectations for the Mueller report, House Democrats are busily probing new avenues of potential criminal or unethical conduct involving President Donald Trump, including allegations of financial mismanagement and foreign-influence peddling surrounding his inauguration. Last month, House Intelligence Committee Chairman Adam Schiff sent a letter requesting documents from Stephanie Winston Wolkoff, a longtime friend of First Lady Melania Trump who had a lead role in planning the events leading up to the president’s swearing-in, and who later served as an unpaid senior adviser in the East Wing. The letter, which was sent to Wolkoff’s lawyer, asks her to turn over information related to efforts by foreign individuals or entities to support or influence Trump’s campaign, transition, and administration. Schiff, who has asked Wolkoff to participate in a voluntary interview, is particularly interested in any communications involving Russia, the United Arab Emirates, Qatar, Saudi Arabia, and other foreign governments.

The document request represents one portion of a broader Democratic effort to build on the work begun by Robert Mueller, who handed his completed report on Russian election meddling to Attorney General William Barr last month. In the course of his investigation, Mueller reportedly looked into other allegations of foreign influence over Trump and his associates, but Democrats are pushing further. In his letter, Schiff asked Wolkoff for documents related to communications with foreign officials related to any gifts, offers, solicitations, or contributions to Trump and the Trump Organization; Trump’s son-in-law, Jared Kushner, and his “business interests”; and Trump’s daughter Ivanka Trump and her business dealings. More broadly, Democrats on the Intelligence Committee have asked for a host of information about the inaugural planning, including organization charts and employee information; complete donor lists and due diligence related to donations the inaugural committee received; inaugural budgets and invoices; guest lists for the events; any payments made directly by donors to vendors; and any effort to shield the identity of donors.

The committee also requested all documents supplied in response to any subpoenas made by Congress, the special counsel’s office, or the Southern District of New York. As part of its sweep last April, when the S.D.N.Y. executed search warrants of Michael Cohen’s residence, hotel room, and office, investigators came across recordings between Cohen, Trump’s longtime lawyer, and Wolkoff, on which the two discussed her concerns about exorbitant inaugural spending and how the planning was managed, as well as how involved she said the Trump family was in the process.

In early October, the United States attorney for the Southern District signed off on a grand-jury subpoena, which Wolkoff was prohibited from disclosing for 180 days. The subpoena, which initially gave Wolkoff roughly two weeks to appear, asked her to produce documents related to the inaugural committee. She has been cooperating with the investigation, sharing thousands of documents and e-mails she saved, and is not considered a target, according to a person familiar with the matter. (Wolkoff declined to comment. A spokesman for the S.D.N.Y. declined to comment.)

Wolkoff’s pending cooperation with Congress and her involvement with the investigation out of the Southern District point to the ways in which she could be helpful to investigators going forward. The document requests also highlight what are potentially some of the biggest threats to Trump, his family, and his businesses, regardless of what is revealed in Mueller’s final report. While Wolkoff had an insider’s view into Trumpworld, as a point person for the inauguration and an adviser to Melania, she is also just one of dozens of individuals and entities who have received document requests from Democrats in recent weeks. Following the first portion of Cohen’s testimony on Capitol Hill earlier this year, the House Judiciary Committee requested documents from 81 individuals and entities, including the inaugural committee and its chairman, Tom Barrack. (Wolkoff was not asked for documents as part of that round of requests, though the committee had said it expects to extend requests to others in subsequent rounds.)

The Oversight Committee is also probing the White House over its security-clearance protocol, of which Wolkoff has intimate knowledge. As I reported earlier this year, Wolkoff’s contract with the White House was terminated in 2018, when the White House instilled new security protocols in the wake of the Rob Porter scandal. A member of the White House Counsel’s Office called her on February 20, 2018, to let her know that the White House would be terminating all gratuitous-services agreements, including hers. It had nothing to do with her work on the inauguration, this person told her; it was part of an administration-wide crackdown. “I am sorry that the professional part of our relationship has come to an end, but I am comforted in the fact that our [friendship] far outweigh[s] politics,” Melania wrote her in an e-mail later that day. “Thank you Again! Much love.”