A Justice Department ethics office has received requests for advice and issued guidance concerning acting attorney general Matthew G. Whitaker’s involvement in the special counsel’s investigation of Russian interference in the 2016 election, according to Justice Department records.

It’s unclear who made the requests to the Justice Department’s Professional Responsibility Advisory Office, which provides professional and ethics advice to government lawyers and department leaders, and what advice, guidance or recommendations the office provided. But the records’ existence shows, for the first time, that questions about Whitaker’s potential control over an investigation that implicates President Trump are a point of discussion within the Justice Department.

Since Trump appointed Whitaker last month, the Justice Department has refused to say if he has consulted ethics officials, or plans to, about whether he should recuse himself from the Russia probe. Whitaker was publicly critical of the investigation before his appointment and has faced pressure, mostly from Democrats, not to take a supervisory role.

Justice Department officials have said Whitaker would follow Justice Department procedures for handling ethics issues that may arise.

The advisory office acknowledged it had found the records in response to a Freedom of Information Act request filed by Benjamin Wittes and Scott Anderson of the Lawfare blog, who shared the office’s response with The Washington Post.

They had asked for “requests for advice, authorizations, determinations, guidance, or legal issues” arising from Whitaker’s possible involvement in or supervision of the Russia probe, as well as “advice, guidance, or written opinions that [the office] has provided regarding ethical or legal issues” arising from Whitaker’s role.

The office said it had found 13 pages of records that were responsive to those requests. Wittes and Anderson also asked for any “authorizations or determinations” that were made, but the office said it found no records, suggesting it may not have reached formal conclusions about whether Whitaker should oversee the probe.

The office said it was withholding all of the documents, citing a legal exemption that allows the government to keep private any internal communications that might be protected by attorney-client privilege or could be considered deliberative in nature.

The question of Whitaker’s possible recusal has dogged him since Trump appointed the former U.S. attorney to replace Jeff Sessions, whom the president had accused of disloyalty for recusing himself from the Russia probe. Whitaker had been serving as Sessions’s chief of staff at the time Trump ousted him.

Before joining the Trump administration, Whitaker appeared on cable news to praise the president and criticize the probe, led by former FBI director Robert S. Mueller III.

Appearing on CNN in July 2017, Whitaker mused about disrupting the probe by starving it of funds.

“So I could see a scenario where Jeff Sessions is replaced with a recess appointment,” Whitaker said then, “and that attorney general doesn’t fire Bob Mueller, but he just reduces his budget to so low that his investigation grinds to almost a halt.”

Before Whitaker’s appointment, the deputy attorney general, Rod J. Rosenstein, had been overseeing Mueller’s work.

As a practical matter, it appears Rosenstein may still be filling that role. Trump’s legal team views him as the day-do-day supervisor, according to people familiar with the matter. Trump’s lawyers were referred to Rosenstein, and not Whitaker, when they raised a concern before Thanksgiving about a reference to Trump in draft court documents, people familiar with the discussion said.

Three Senate Democrats have filed a lawsuit challenging the constitutionality of Whitaker’s appointment, arguing that he cannot serve in the position because he hasn’t been confirmed by the Senate.

Maryland’s attorney general has also challenged Whitaker’s appointment in court, and a lawyer has asked the Supreme Court to step in and say that someone else should take Whitaker’s place as the acting attorney general.

The Justice Department’s office of legal counsel issued an opinion saying Whitaker’s appointment as an acting official was legal, and while it has occurred only sparingly in the past 20 years, it was a more common occurrence in the federal government before 1870.

Republicans have also been skeptical that Whitaker has the career experience to serve in one of the most demanding and sensitive roles in government. And questions have risen about his work for a patent firm that the federal government hit with sanctions.

Whitaker’s future as acting attorney general and his role in the Mueller probe may soon be settled following Trump’s announcement Friday that he will nominate William P. Barr as the next attorney general.

Carol D. Leonnig and Devlin Barrett contributed to this report.