During independent counsel Kenneth W. Starr’s tumultuous investigation of President Bill Clinton in the 1990s, there were loud objections and even lawsuits filed over the fact that information meant to be kept secret was being leaked to the press by Starr’s staff.

Among those guiding the journalists and authors was a young lawyer named Brett M. Kavanaugh, now a federal judge and President Trump’s nominee to the Supreme Court.

Interviews with those who dealt with Kavanaugh at the time and documents relating to his confirmation show the nominee to be a savvy Washington source — a go-to member of Starr’s team who dealt with conspiracy theorists about the Clintons and the death of aide Vincent Foster and found ways to defend the investigation’s integrity against broadsides from the White House.

Now Senate Democrats are ­exploring whether Kavanaugh crossed a line in his private communications with outsiders and revealed grand-jury testimony related to Foster’s suicide or other matters then under scrutiny in Starr’s wide-ranging investigation of Bill and Hillary Clinton.

This week, Senate Democrats contacted an author who said Kavanaugh was offered as a confidential source by Starr’s deputies, and the lawmakers were part of a successful effort to persuade a judge to order the release later this week of a sealed 1999 report into alleged grand-jury leaks by Starr’s office.

Kavanaugh’s confirmation hearing before the Senate Judiciary Committee is scheduled for Sept. 4.

The White House declined to comment.

Senior U.S. District Judge Royce Lamberth of the District of Columbia on Wednesday afternoon granted the request from the watchdog organization American Oversight to release the 62-page report, which was written in 1999 by Judge John Kern III, acting as a special master. Lamberth said the report should be released by the National Archives as quickly as possible but no later than 3 p.m. Friday.

“There have been 20 years of rumors and speculation about who was doing the leaking on the Starr commission, and just a week after American Oversight asked for this report to be unsealed, we may finally get an answer,” said American Oversight’s executive director, Austin Evers. “If Judge Kavanaugh was involved in improper leaking of confidential information, the Senate Judiciary Committee and the American people have a right to know before he is confirmed to a lifetime position on the Supreme Court.”

Justice Department lawyer Elizabeth J. Shapiro had written earlier in the day that the report “investigates allegations of wrongdoing but ultimately finds no violations of anything within the Special Master’s investigative mandate.”

Kavanaugh, in a questionnaire submitted to the Judiciary Committee last month, acknowledged that he had been a source for several books written about the Starr investigation. In addition, “I have also spoken to reporters on background as appropriate or as directed,” he said.

One of the reporters he talked with was Dan Moldea, who told The Washington Post that Kavanaugh “was the designated person whom the [Office of the Independent Counsel] puts with people like me.” Moldea wrote a book called “A Washington Tragedy: How the Death of Vincent Foster Ignited a Political Firestorm.”

Moldea contrasted the ease with which reporters were able to get inside information about the Starr probe with the strict secrecy widely attributed to special counsel Robert S. Mueller III’s investigation of President Trump and Russian interference in the 2016 election.

“I doubt that Robert Mueller’s people are doing that,” Moldea said.

In meetings with The Post, Moldea played 20-year-old recordings of his conversations with Starr deputies. He said he also played the recordings for Judiciary Committee lawyers Saturday in a meeting they requested.

The recordings suggest that Starr’s top deputies referred Moldea to Kavanaugh for answers to questions about the Foster matter.

Moldea said that Kavanaugh called him and that they arranged to have lunch on Jan. 19, 1998, at the Old Ebbitt Grill near the White House.

Moldea said he did not record that conversation, and he declined to discuss it in detail. “I am not going to describe the substance of my off-record conversations with Brett Kavanaugh,” he said.

At the time of their meeting, Kavanaugh had left Starr’s office after concluding an investigation of Foster’s death, which was ruled a suicide, and was working at a law firm. He later returned to the independent counsel’s office to work on other aspects of the Clinton investigation.

Moldea said he has no evidence that Kavanaugh broke any laws, such as sharing information that was presented to a grand jury. In an affidavit he prepared at the time, he said he wanted to be “clear” that he was not alleging “any wrongdoing” by Kavanaugh or another lawyer with the independent counsel’s office whom he interviewed.

In his book, Moldea describes an interview with an unnamed person at the Old Ebbitt Grill who he said was discussing speculation that Hillary Clinton had an affair with Foster. The allegation was never proved, but it circulated widely among conspiracy theorists after Foster’s death.

The reference to the discounted rumor of an affair is prompting questions from Judiciary Committee Democrats.

They note that two grand juries had convened to investigate the Whitewater controversy, including issues related to Foster’s death. Hillary Clinton testified before one of them in January 1996.

In a 1995 memo, Kavanaugh referenced the allegations.

“I note that we have asked numerous people about Foster’s alleged affair with Mrs. Clinton, but have received no confirmation of it,” Kavanaugh wrote to Starr and other lawyers. “If we want to pursue this line of investigation further, however, we should ask Mrs. Clinton about the alleged affair at her next interview.”

It is not contested that Starr’s staff spoke with reporters on a non-attribution basis during the investigation. Starr acknowledged that in a magazine interview at the time, saying it was necessary to protect the integrity of the investigation in the face of White House complaints about it.

In February 1998, Starr’s office filed 96 declarations from past and present employees denying under threat of perjury that they had any involvement with illegal leaks related to the Monica Lewinsky scandal. Kavanaugh, who did not rejoin the staff until a couple of months later, was not among those submitting the declarations.

Bill Clinton’s attorneys, though, went to court about the leaks.

In a September 1998 order, U.S. District Judge Norma Holloway Johnson said an initial, cursory review of 24 news reports — from television, magazines and newspapers — suggested that the independent counsel’s office had illegally disclosed grand-jury information.

Johnson, then the chief judge of the court in the District of Columbia, appointed Kern to serve as a “special master” and to undertake a “complete and thorough review” of the allegations.

Kern was tasked with collecting evidence, with the authority to subpoena documents such as phone records, letters, notes, memos and calendar entries and to interview former and current members of the office.

His findings, Johnson wrote, would help her determine whether any members of Starr’s office had in fact violated federal rules prohibiting the disclosure of grand-jury material.

But an appeals court panel said Johnson’s reading of the law involving the release of grand-jury proceedings was too expansive, and it declined to authorize the release of the Kern report.

Michael Kranish and Ann E. Marimow contributed to this report.